physical science midterm study guide...

Physical Science Midterm Study Guide 2014

SPS8. Students will determine relationships among force, mass, and motion.

a. Calculate velocity and acceleration.

b. Apply Newton’s three laws to everyday situations by explaining the following:

Inertia

Relationship between force, mass and acceleration

Equal and opposite forces

c. Relate falling objects to gravitational force

d. Explain the difference in mass and weight.

e. Calculate amounts of work and mechanical advantage using simple machines.

SPS7. Students will relate transformations and flow of energy within a system. a. Identify energy transformations within a system (e.g. lighting of a match).

b. Investigate molecular motion as it relates to thermal energy changes in terms of conduction,

convection, and radiation.

c. Determine the heat capacity of a substance using mass, specific heat, and temperature.

d. Explain the flow of energy in phase changes through the use of a phase diagram.

SPS9. Students will investigate the properties of waves. a. Recognize that all waves transfer energy.

b. Relate frequency and wavelength to the energy of different types of electromagnetic waves and

mechanical waves.

c. Compare and contrast the characteristics of electromagnetic and mechanical (sound) waves.

d. Investigate the phenomena of reflection, refraction, interference, and diffraction.

e. Relate the speed of sound to different mediums.

f. Explain the Doppler Effect in terms of everyday interactions.

SPS10. Students will investigate the properties of electricity and magnetism. a. Investigate static electricity in terms of

friction

induction

conduction

b. Explain the flow of electrons in terms of

alternating and direct current.

the relationship among voltage, resistance and current.

simple series and parallel circuits.

c. Investigate applications of magnetism and/or its relationship to the movement of electrical charge as

it relates to

electromagnets

simple motors

permanent magnets

SPS2. Students will explore the nature of matter, its classifications, and its system for naming types of

matter. a. Calculate density when given a means to determine a substance’s mass and volume.

SPS5. Students will compare and contrast the phases of matter as they relate to atomic and molecular

motion. a. Compare and contrast the atomic/molecular motion of solids, liquids, gases and plasmas.

b. Relate temperature, pressure, and volume of gases to the behavior of gases.

SPS8: Students will determine relationships among force, mass, and motion.

a. Calculate velocity and acceleration.

Velocity is speed in a given direction

1. speed in a particular direction

2. formula: velocity = displacement (distance and direction)/Time

Velocity Problem: What is the average velocity of a commercial jet that travels west from New York to

Los Angeles (4800 km) in 6.00 hours?

Velocity = distance/ time

Velocity =

Velocity =

Acceleration is the rate of change in velocity.

1. the rate at which velocity changes

2. formula: acceleration = final velocity-initial velocity/time

or acceleration =

t

VVa 0

3. Acceleration occurs if either of these two conditions exist.

a. The speed of an object is changing. It can be increasing or decreasing.

b. The direction of the movement is changing.

Sample Problem: If a car accelerates from 5 m/s to 15 m/s in 2 seconds, what is the car's average

acceleration?

V =

t

VVa 0

Vo = a=

t =

SPS8: Students will determine relationships among force, mass, and motion. b. Apply Newton’s three laws to everyday situations by explaining the following:

Inertia

Relationship between force, mass and acceleration

Equal and opposite forces

Newton's Laws of Motion are three laws which describe the relationship between forces acting on an

object and the motion of that object.

1. An object that is at rest or in uniform motion tends to stay at rest or in uniform motion,

respectively, until acted upon by an outside force.

2. The net force on an object is equal to the mass of the object multiplied by the acceleration of the

object.

3. For every action, there is an equal and opposite reaction.

But what exactly is meant by the phrase unbalanced force? What is an unbalanced force? In pursuit of an

answer, we will first consider a physics book at rest on a tabletop. There are two forces acting upon the

book. One force - the Earth's gravitational pull - exerts a downward force. The other force - the push of

the table on the book (sometimes referred to as a normal force) - pushes upward on the book.

Since these two forces are of equal magnitude and in opposite directions, they balance each other. The

book is said to be at equilibrium. There is no unbalanced force acting upon the book and thus the book

maintains its state of motion. When all the forces acting upon an object balance each other, the object

will be at equilibrium; it will not accelerate.

A book sliding to the right across a tabletop (the forces acting upon the book are shown below).

The force of gravity pulling downward and the force of the table pushing upwards on the book are of

equal magnitude and opposite directions. These two forces balance each other. Yet there is no force

present to balance the force of friction. As the book moves to the right, friction acts to the left to slow the

book down. There is an unbalanced force; and as such, the book changes its state of motion. The book is

not at equilibrium and subsequently accelerates.

A. Newton’s Laws of Motion

1. The Law of Inertia or Newton’s First Law: An object at rest tends to stay at rest and an object in

motion tends to remain in motion in a straight-line path unless acted on by an unbalanced force.

a. Inertia is the resistance of any physical object to a change in its state of motion or rest.

b. Applications:

i. This activity is similar to the magician's trick of pulling a tablecloth out from

under dishes on a table. Because the dishes have inertia, they will stay at rest

unless acted on by some unbalanced force. If the tablecloth is really smooth

and is pulled out fast enough, there is not enough friction created to cause the

dishes to move. DO NOT TRY THIS AT HOME WITHOUT PARENT

PERMISSION!

ii. People are often thrown from automobiles in wrecks because the car comes to

a sudden stop, but the person has a tendency to stay in motion.

iii. The ride is much smoother on a cruise ship than a fishing boat, because the

cruise ship is more massive and is not affected as much by the waves.

2. Newton’s Second Law: The acceleration of an object is directly proportional to the applied force and

inversely proportional to its mass.

F=ma F= force; m = mass; a = acceleration

This law also means that force is directly proportional to acceleration and mass. Thus, if the force placed

on an object is doubled, the acceleration of the object will also be doubled. In addition, the mass of the

object and the acceleration of the object are inversely proportional. If the mass of an object is halved, the

acceleration on the object is doubled (when the force remains the same).

An example of this law would be if a bowling ball and a soccer ball were dropped from the same height

at the same time. Gravity accelerates the objects at the same speed (as it does for all objects), so the

difference in forces as the balls hit the ground would be due to the mass of the ball. Thus, the bowling

ball, which has the larger mass, would hit the ground with a greater force.

Sample Problem: What is the force exerted by a 2 kg mass that accelerates at 3 m/sec/sec?

Mass = 2 kg F=ma

acceleration = 3 m/sec/sec F =

F=

(1 newton = 1 kilogrammeter/second/second)

So the correct answer is ____________.

3. Newton’s Third Law: For every action there is an equal and opposite reaction.

In other words, whenever object A exerts a force on object B, object B exerts an equal force (in the

opposite direction) on object A. Both forces are exerted along the same line.

For example, when a bird flies, its wings push downward on the air. The air then pushes upward on the

wings (and the bird). The action of the bird flapping its wings (exerting a force on the air) helps the bird

fly (the air exerting a force on the bird).

a. If object A exerts a force on object B, then object B exerts an equal force on object A

in the opposite direction.

b. Consequences: Forces always exist in pairs. It is impossible for you to push on

something without it pushing back. Newton’s Third law can be used to explain the

motion of rockets and balloons. As the gases exit the balloon or rocket, they push it in

the opposite direction.

Motion depends on the observer’s frame of reference


c. Relate falling objects to gravitational force

In the late 1600's, Sir Isaac Newton developed the law of universal gravitation. According to this law,

every object exerts gravitational force on every other object.

The amount of gravitational force that an object is able to exert depends on:

•the object's mass

•the distance between the objects

So, in the example of the falling apple, since the Earth has much more mass than the apple, the apple is

pulled toward the Earth more than the Earth is pulled toward the apple. The net unbalanced force points

in the direction of the Earth.

Gravitational force also depends on the distance between two objects. In fact, differences in distance have

a greater effect on gravity than do differences in mass. For example, the gravitational force between the

Earth and the Sun is stronger than the force between Jupiter and the Sun. Even though Jupiter has a

greater mass than the Earth, the shorter distance between the Sun and the Earth makes the force between

the Sun and the Earth much stronger than the force between the Sun and Jupiter.

The value of a gravitational force can be calculated using the law of universal gravitation in its

mathematical form, shown below.

In the equation, F is the force of gravity, G is the universal gravitational constant, m1 and m2 are the

masses of the two objects, and d is the distance between them.


d. Explain the difference in mass and weight.

Mass is defined as the amount of matter an object has. Weight is defined as the force of gravity on a

mass.

A spring scale can be used to measure weight. Mass is the same on the Moon as it is on Earth, but the

weight of an object is 1/6 as much on the Moon as on the Earth.

The weight of an object is the force of gravity on the mass:

F = mg or W = mg

Where:

•F is the force of gravity on the mass in newtons (N) or pounds (lbs)

•m is the mass of the object in kg or pound-mass

•g is the acceleration due to gravity (9.8 m/s2 or 32 ft/s2)

•W is the weight in N or lbs


e. Calculate amounts of work and mechanical advantage using simple machines

WORK

Work is force exerted on an object that causes the object to move some distance

Force without moving a distance yields NO WORK!!.

Work can be defined by the following equation:

W = F x d

Joule = Newton x Meter

where . . . F = the force applied to an object and

d = the distance the object moves in the direction of the force.

Simple Machines A machine is a device that makes work easier or more effective.

A machine makes work easier by changing the amount of force, the distance covered or by changing the

direction of the force

There are six simple machines:

•the inclined plane

A plane is a flat surface. When that plane is inclined, or slanted, it can help you move objects

across distances. And, that's work! A common inclined plane is a ramp. Lifting a heavy box onto a

loading dock is much easier if you slide the box up a ramp--a simple machine.

•the wedge

When you can use the edge of an inclined plane to push things apart or when the incline plane can

be moved then, the inclined plane is a wedge. So, a wedge is actually a kind of inclined plane. An axe

blade is a wedge. Think of the edge of the blade. It's the edge of a smooth slanted surface.

•the screw

an inclined plane wrapped around a cylinder. A screw can convert a rotational force (torque) to a

linear force and vice versa.

•the lever

A lever is a rigid bar that "pivots" (or turns) against a "fulcrum" (or a fixed point).

There are three classes of levers:

1. First Class Lever: The input & output forces are in opposite directions. The fulcrum is

between the input & output forces. Examples include: nail remover, paint can opener

scissors, seesaw.

2. Second Class Lever: The input & output forces are in the same direction. Input force is

farther away from the fulcrum than the output force. Examples include: wheel barrow, door,

nutcracker.

3. Third Class Lever: The input & output forces are in the same direction. The input force is

closer to the fulcrum than the output force. Examples include: rake, shovel, baseball bat and

fishing pole.

•the pulley

In a pulley, a cord wraps around a wheel. As the wheel rotates, the cord moves in either direction.

Now, attach a hook to the cord, and you can use the wheel's rotation to raise and lower objects.

•the wheel and axle

It includes two circular objects attached together about a common axis. Wheel is the large

cylinder. Axle is the small cylinder

The inclined plane, the wedge, and the screw all make work easier by requiring a smaller force to be

applied through a longer distance. For example, it requires more force to pick a box straight up than it

does to push it up a ramp, but the box travels a greater distance up a ramp than it would if it were simply

picked up.

The lever, the pulley, and the wheel and axle make work easier by changing the direction of the applied

force. For example, instead of having to pull a bucket of water up out of a well, a rope can be attached to

the bucket and wrapped around a pulley. The pulley makes work easier because it lifts the bucket up by

allowing the rope to be pulled down.

Efficiency

The efficiency of a machine compares the work output to the work input. The formula for efficiency is:

efficiency = (work output/work input) x 100%

The work done by the machine is called the work output. The work output is equal to the force applied by

the machine multiplied by the distance through which the force is applied.

The work done on the machine is called the work input. The work input is equal to the force applied on

the machine multiplied by the distance through which the machine moves.

For example, if you pull down on the handle of a shovel to lift a pile of dirt, the work input is equal to the

force that you applied to the handle times the distance that the handle moved. The work output is equal to

the force the shovel exerted on the dirt times the distance the dirt moved.

Although machines make work easier, they do not multiply work; that is, the work output can never be

greater than the work input, and the efficiency of a machine can never be greater than 100%.

Mechanical Advantage There are two forces involved when using machines...

•the effort force (FE) is the force that is applied to the machine

•the resistance force (FR) is the force applied by the machine

The mechanical advantage of a machine is the number of times the machine multiplies the effort force.

In general, it is calculated using the formula... MA = FR / FE or MA

Mechanical advantage involving distance:

A machine has distance mechanical advantage when the output distance is greater than the applied

distance.

There are times when you want to apply a force a short distance to increase the distance an object moves.

One good example is when you peddle a bicycle. The distance you move the peddles on a bicycle are

much less than the distance moved on the circumference of the tires.

The bicycle and other machines may provide a distance mechanical advantage. The equation for this is:

MAd = dL/dE

where

•MAd is the distance mechanical advantage

•dL is the distance the load moves or the output distance

•dE is the distance the effort moves or the input distance

Alternately, the mechanical advantage of each of the six simple machines can be determined using the

following information:

•inclined plane - the mechanical advantage equals the length of the plane divided by the height of the

plane

•wedge - the mechanical advantage equals the length of the sloping side of the wedge divided by the

width of the thick end of the wedge

•screw - the closer the threads are, the greater the mechanical advantage

•lever - the mechanical advantage equals the length of the effort arm divided by the length of the

resistance arm

•pulley - the mechanical advantage equals the number of rope segments that directly support the object

being moved

•wheel and axle - the mechanical advantage equals the radius of the wheel divided by the radius of the

axle

1. Define: Velocity, Acceleration, Inertia, Force, Mass, weight, work, mechanical advantage, simple machines.

2. Write the Metric Units for: Velocity, Acceleration, Inertia, Force, Mass, weight, work, mechanical advantage,

simple machines.

3. Give two everyday situations for Newton’s Laws:

a. Inerita,

b. Relationship between force, mass and acceleration

c. Equal and opposite forces

4. Explain how gravity affects falling objects.

5. Explain how the affects of gravity changes when you travel from the earth to the moon.

6. Discuss the difference between mass and weight.

7. List and describe six simple machines.

8. Write the equations for and rearrange solving for all variables:

a. Velocity

b. Acceleration

c. Work

d. Mechanical Advantage

SPS7. Students will relate transformations and flow of energy within a system.

a. Identify energy transformations within a system (e.g. lighting of a match).

Energy is the ability to do work.

There are two types of energy:

Kinetic Energy: the energy of motion

Potential Energy: stored energy

Potential Energy can be changed into Kinetic Energy. Also Kinetic Energy can be changed into Potential

Energy

Energy can take several different forms, including:

•mechanical energy

•electrical energy

•heat energy

•light energy

•sound energy

•chemical energy

1. Mechanical energy is the energy that an object has due to its motion or its position. It can be further

classified as kinetic energy, or energy of motion, and potential energy, or stored energy of position.

Mechanical energy is present in:

•a moving car

•a book on a desk

•a ball that is thrown

2. Electrical energy moves charged particles from one place to another. When a conductor—something

that electrons can move through—makes a path from one end of a battery to the other or one side of

an outlet to another, electrons begin flowing through it, creating electricity. The path along which

they flow is a circuit. These moving electrons flow through wires as a current, or a continuous flow

of electrically charged particles. These currents can do work, converting their electrical energy to

another type of energy (e.g., heat, light, sound, mechanical).

Example:

A wire is plugged in to a power outlet on a wall. The electrical energy that flows through the wire

transfers into:

•light energy when it reaches a lamp.

•mechanical energy when it reaches a fan.

•sound energy when it reaches a radio.

•heat energy when it reaches a microwave.

3. Heat energy can be created when matter undergoes a chemical change (burning wood or coal) or

when it is produced by another form of energy. It can transfer from a warmer object to a colder

object.

Examples of heat energy include:

•when wood or other fuels are burned to produce heat

•when electric energy is converted to heat in appliances

◦hair dryer

◦microwave

4. Light energy is a type of wave energy, which is transferred and created by other types of energy.

Light energy can also come from the Sun, which is referred to as solar energy.

Light energy can be transferred from (and to) other energy types, such as:

•when electrical energy makes a lightbulb light up

•when light energy is absorbed by plants and made into chemical energy (food)

5. Sound energy is the energy of sound waves as they travel.

Sound energy can be created by other forms of energy, such as:

•mechanical energy, when drums are played

•electrical energy, when a radio is turned on

6. Chemical energy is the energy found in chemical compounds, such as food or fuel.

Energy Transformation Sample Questions:

Question 1: Jenna has connected a fan, a radio, and a lamp to an extension cord, which is plugged into the

wall. The electrical energy flowing through the extension cord will transfer to which type of energy as it

powers the appliances?

A. mechanical energy

B. sound energy

C. light energy

D. all of these

Explanation: The electrical energy flowing through the extension cord with transfer to mechanical

energy as it powers the fan, sound energy as it powers the radio, and light energy as it powers the lamp.

Question 2: Mike is playing the drums. As he beats the drums, the mechanical energy of moving the

drumsticks is converted to _______.

A. sound energy

B. light energy

C. electrical energy

D. heat energy

Explanation: The mechanical energy of beating the drumsticks is converted into sound energy when

Mike plays the drums. When most instruments are played, the musician applies mechanical energy to the

instrument, and sound energy results from the instrument, such as in playing the piano, a harp, or a

trumpet.

Question 3: A plant receives _______ energy and transforms it into chemical energy for food.

A.heat

B.mechanical

C.light

D.sound

Explanation: A plant receives light energy from the Sun, and uses that to make chemical energy for food.


b. Investigate molecular motion as it relates to thermal energy changes in terms of conduction,

convection, and radiation.

Heat always flows from hotter objects to colder objects, until equilibrium is reached. It will not

spontaneously flow in the opposite direction. Heat is measured in Joules (J) and can be transferred by

conduction, convection, and radiation.

Conduction

•Conduction is the transfer of energy through matter by the direct contact of its particles.

•Conduction works best when transferring energy through solids (since the particles are closer

together in a solid), but it will also transfer energy in liquids and gases.

•This occurs when a source of heat speeds up the particles in one part of the object. These

particles strike other particles in the object which strike other particles, in turn, until the kinetic

energy of all the particles in the object increases. The increase in kinetic energy causes an

increase in temperature and an increase in the object's thermal energy.

A conductor is something that lets heat and electricity go through it.

Think of a hot summer day. You sit on a shiny metal slide, OUCH! It's very hot and burns your legs!

The slide is made of metal, it is a good conductor.

An insulator is something that does not let heat and electricity go through it easily.

If you slide down a plastic slide, like on our playground, it is very warm, but it will not burn you like a

metal slide. Plastic is a good insulator.

Convection

•Convection is the transfer of heat through a fluid such as a liquid or a gas.

•As the liquid or gas is heated, the hot part expands and becomes less dense.

•Currents facilitate the transfer of heat by convection through liquids and gases.

Radiation

•Radiation is the transfer of energy through rays or waves.

•The Sun heats the Earth by radiation.

Heat Transfer Questions:

1. You might see the air shimmering over a radiator (convection),

2. put your hand on a warm spoon that's been sitting in a hot bowl of soup (conduction), or

3. notice that the sun shine feels warm on your skin (radiation).


1. Determine the heat capacity of a substance using mass, specific heat, and temperature.

The first law of thermodynamics is the application of the conservation of energy.

States: that the increase in thermal energy of a system equals the work done on the system plus the heat

added to the system.

Endothermic vs. Exothermic

Exothermic- heat energy EXITS the system

- ex. Combustion, evaporation of water

- surroundings usually feel warmer

Endothermic- heat energy ENTERS the system

- ex. Cold packs, melting ice

- surroundings usually feel cooler

Specific heat capacity is also known as ‘specific heat’. It is the energy required to raise 1 gram of a chemical

by 1 degree Celsius. It has a unit of J/g°C (or Joules per degree Celsius per gram)

Each material is able to "hold" a certain amount of thermal energy at a given temperature, due to what

we call its specific heat. Think of the wide range of temperatures that your feet encounter during a day at the

beach. The water may seem cold while the sand feels quite warm. The wood on the boardwalk may feel

comfortable, but the blacktop in the parking lot is burning hot. Things will heat up at different rates, due, in

part, to their different specific heat values.

So, as you see, temperature is one of the factors that affect the thermal energy of a substance. What is heat?

Heat is the transfer of thermal energy from a hotter to a colder object. What we think of as "cold" is really the

absence of heat. An object with at a higher temperature can release more heat than the same object at a lower

temperature, but temperature is only one of the factors that affect the amount of heat an object can transfer.

The factors that affect the amount of heat are the same as the factors that affect thermal energy, for reasons

that should now be clear to you. Thermal energy is only measurable as heat, during heat transfer. The

amount of heat transferred can be found according to the following formula:

amount of heat transferred = mass x specific heat x change in temperature

Q = m * c * ∆T

Sample Problem:

C = q/m∆T, where q = heat energy, m = mass, and T = temperature.

Remember, ∆T = (Tfinal – Tinitial).

Show all work and proper units.

1. A 15.75-g piece of iron absorbs 1086.75 joules of heat energy, and its temperature changes

from 25°C to 175°C. Calculate the specific heat capacity of iron.

2. To what temperature will a 50.0 g piece of glass raise if it absorbs 5275 joules of heat and its

specific heat capacity is 0.50 J/g°C? The initial temperature of the glass is 20.0°C.


d. Explain the flow of energy in phase changes through the use of a phase diagram.

Matter can be found in three main states—solid, liquid, and gas—and can move among these states. For

instance, solid water can be melted to form liquid water, and liquid water can be evaporated to form water

vapor. When matter is transformed from one phase to another, it is said to undergo a phase change or change

of state.

The different types of phase change are:

Melting transformation of a solid into a liquid

Freezing transformation of a liquid into a solid

Sublimation transformation of a solid into a gas without first becoming a liquid

Deposition transformation of a gas into a solid without first becoming a liquid

Vaporization transformation of a liquid into a gas

Evaporation vaporization that takes place at the surface of a liquid

Condensation transformation of a gas into a liquid

Phase Changes are Physical Changes

Phase changes are physical changes because only the physical properties of the matter change. The mass,

chemical composition, and chemical properties of the matter do not change when the substance changes state.

A few of the physical properties which can change with a change of state are density, viscosity, and

appearance.

The atoms or molecules in a gas have the same mass as when they are in solid or liquid form, but they are

much further apart. This results in a lower density. In fact, the density of a gas is always lower than the same

material in liquid or solid form.

Usually, liquids are less dense than the same substance as a solid. Water is a notable exception to this rule.

The ability of liquids to flow is described as their viscosity. Liquids experience a change in viscosity when

they become a solid or a gas because the particles become either too close together or too far apart to have the

ability to flow.

Phase Changes and Heat

Atoms or molecules in a solid are oriented close together in a regular arrangement. For the particles in a solid

to overcome the attractive forces that are holding them in this arrangement, heat must be added to the solid.

Atoms or molecules in a liquid are able to move around one another, but are still close together. Heat must

also be added to allow the molecules to break away from one another and become a gas. Heat must be gained

or lost for matter to change phases. Atoms or molecules in liquids are typically farther apart and are arranged

more randomly than those in solids. For the particles in a liquid to become more ordered, heat must be

removed from the liquid.

Since particles in gas form are arranged in a way that is even less orderly than in liquids, heat must

also be added when gas is formed, either through boiling or sublimation. To form liquids from gases

(condensation) or solids from gases (deposition), heat energy must be removed from the gas.

When heat is added to a substance, the energy of the substance increases; When heat is removed from

a substance, the energy of the substance decreases.

The following diagram shows the relationship between heat and energy for each state of matter.


1. Define: transformation, conduction, convection, radiation, heat capacity, specific heat, temperature, phase

change, phase diagram

2. List six categories of energy (ie, electrical, thermal, nuclear, etc.) and give one everyday example of a

transformation between two of the categories.

3. Give a description of everyday examples of conduction, convection, and radiation.

4. Write the equation for heat capacity:

a. Rearrange the equation to find the mass.

b. Rearrange the equation to find the Final Temperature.

c. Rearrange the equation to find the Initial Temperature.

d. Rearrange the equation to find the energy flow.

5. What are the states of matter?

6. Discuss phase change by water.

7. Draw and discuss the phase diagram. Label the diagram with each state of matter and the energy flow.

SPS9. Students will investigate the properties of waves.

a. Recognize that all waves transfer energy.

Wave is a transfer of energy, in the form of disturbance through some medium, without translocation

(movement) of the medium. A wave is a periodic disturbance which travels through a medium from one

point in space to the others.

Basic properties of waves include:

Energy is transferred from one place to another in a wave motion.

Motion of the medium (particles of the medium) is usually periodically vibratory.

Only the shape or form of wave travels, not the medium.

1. All waves carry energy through matter or space. They do not carry matter.

2. Waves carry energy that can be transferred or transformed in interactions with matter or other waves.

3. Waves are energy. Waves carry energy from the source out.

4. Waves are either mechanical or electromagnetic. Which one depends on the source of the vibration.

Transverse Wave: Longitudinal Wave:

•Crest—the highest point of a transverse wave

•Trough—the lowest point of a transverse wave

•Amplitude—the distance from the crest (or trough) of a wave to the rest position of the medium

•Wavelength—the distance between a point on one wave and the identical point on the next wave

•Frequency—the number of wave crests that pass by a point each second; measured in hertz (1 Hz = 1

wave/sec)

•Speed—how fast a wave is traveling; speed (s) = wavelength (λ) x frequency (f)

Types of Waves

Waves can be classified into two groups based on whether or not they require a medium in order to

travel.

1. Mechanical waves require a medium in order to travel from one place to another.

2. Electromagnetic waves do not need a medium.

Mechanical Waves

Any wave that requires a medium, such as air, to transfer energy is known as a mechanical wave. These

waves cannot transfer energy in a vacuum. Sound waves, water waves, and stadium waves (the kind in

which people stand up and then sit down to make a wave) are all examples of mechanical waves.

Ocean waves, such as the ones shown here, are mechanical waves. They cannot move unless there is

some type of material to move through.

Electromagnetic Waves

Any wave that can transfer energy through both a medium and empty space is an electromagnetic wave.

All the waves on the electromagnetic spectrum (radio waves, infrared waves, light waves, ultraviolet

waves, x-rays, and gamma rays) are examples of electromagnetic waves.


b. Relate frequency and wavelength to the energy of different types of electromagnetic

waves and mechanical waves.

Wavelength and Frequency

Low Frequency High Frequency

Radiation is defined by its wavelength, frequency, and energy. The wavelength is the distance between

peaks in the wave, i.e. the distance from crest to crest. If a wave is passing by a point, the frequency is the

time interval between passing peaks. Therefore as the wavelength increases, the frequency decreases (and

vice-versa).

Frequency = Speed of Light / Wavelength (Hertz (Hz) or Cycles per Second are the basic units of

Frequency)

Wavelength = Speed of Light / Frequency (Meter is the basic unit for measuring the wavelength. For

very small wavelengths microns or nanometers are commonly used.)

SPECTRUM BASED ON WAVELENGTH, FREQUENCY, AND ENERGY

The spectrum of waves can be divided into sections based on wavelength, frequency, or energy. The

shortest waves are gamma rays, which have wavelengths of 10e-6 microns or less, carry the most energy,

and have the highest frequencies. The longest waves are radio waves, which can have wavelengths of

many kilometers, carry the least energy, and have the lowest frequencies.

Visible light is a particular band of electromagnetic radiation that can be seen and sensed by the human

eye. This energy consists of the narrow portion of the spectrum, from 0.4 microns (blue) to 0.7 microns

(red). The infrared range starts at the end of the red spectrum with wavelengths greater than 0.7 microns.


c. Compare and contrast the characteristics of electromagnetic and mechanical (sound)

waves.

1. Waves are either mechanical or electromagnetic.

2. Mechanical waves (sound, ocean waves, seismic) require a medium (air, water, ground) to travel

through.

3. Electromagnetic waves are the most common waves in the universe (X-rays, Ultraviolet, radio, and

Light) and can travel through a medium or through the void of space (like the sun’s rays).

4. Mechanical waves are either transverse , longitudinal waves, or a combination of both (i.e. surface

waves)

5. In transverse waves, the wave energy moves perpendicular to the matter in the medium. The high

point in a transverse wave is called the crest and the low point is called the trough.

6. In Compressional / Longitudinal waves, the wave energy moves parallel to the matter in the medium.

The matter in the medium compresses together and expands.

7. The Electromagnetic Spectrum. There are different types of electromagnetic waves. All travel at the

same speed, but they have different wavelengths.


d. Investigate the phenomena of reflection, refraction, interference, and diffraction.

Reflection: when a wave bounces off a surface that it cannot pass through

Refraction: the bending of a wave as it enters a new medium at an angle

Diffraction: the bending of a wave as it moves around an obstacle or passes through a narrow opening.

Interference: the interaction of two or more waves that combine in a region of overlap

Compare destructive and constructive interference. Both are caused by two or more waves

interacting, but constructive interference combines the energies of the two waves into a greater amplitude

and destructive interference reduces the energies of the two waves into a smaller amplitude.


e. Relate the speed of sound to different mediums.

A traveling wave occurs when a vibrating object creates a disturbance in a medium. As particles

in the medium are disturbed, they push or pull their neighboring particles, causing the wave to travel. An

ocean wave is a great example of a traveling wave.

Imagine an ocean wave that has been created by some triggering event (such as wind or an

earthquake). When this wave hits the shoreline, it can move sand, rocks, or living things. Large waves

called tsunamis can cause great destruction to property and habitats.

This example shows how a wave transfers the energy of a triggering event over great distances.

A sound wave is another example of how waves can transfer energy. When you hit a nail with a

hammer, the resulting vibration of the nail, hammer, and other objects causes the nearby air molecules to

vibrate, which causes other nearby air molecules to vibrate. This disturbance continues to travel through

the air. If the vibrations are passed to the air molecules near someone's ear, the small bones in his/her ear

will vibrate. This is how we detect sound. In this way, sound waves transfer the energy of a triggering

event through a medium.

Waves transfer energy differently depending upon the material through which they are traveling.

For example, traveling from a less dense to a more dense material causes the wave to slow down and to

have a shorter wavelength. These changes indicate that the wave is interacting differently with the

medium.

Anyone who has put their ear to a table or listened to a motorboat under water has experienced a

difference in the energy transfer of sound waves through different materials.


f. Explain the Doppler Effect in terms of everyday interactions.

The Doppler effect is a change in the observed wavelength of waves due to motion by the observer or the

wave source. Perhaps the most familiar example of the Doppler effect occurs while waiting at a railroad

crossing—the pitch of the train's horn increases as the train engine approaches and decreases as it moves

away.

For a stationary observer, the frequency of the sound wave they experience from a moving source

is greater as the source approaches, than as it gets farther away. The shortest wavelengths (highest

frequencies) will occur directly in front of the approaching wave source.

The pitches are different because the observer perceives the sound wavelengths to be shorter as

the train approaches and longer as the train moves away. The wavelengths change to the observer

because the distance between the source of the signal and the observer is changing through time. At

constant velocities, this effect is independent of the observer's distance from the source; instead, it is only

dependent on whether the source is approaching or receding.

The Doppler effect can also be observed if the listener is moving and the source of the wave is

stationary. The Doppler effect is evident with all types of waves involving moving sources or observers,

including sound and light. Electromagnetic radiation from objects throughout the universe exhibits the

Doppler effect. Astronomers study this effect to learn more about the universe.


1. Define: wave, frequency, properties, wavelength, electromagnetic wave, mechanical wave,

reflection, refraction, interference, diffraction, medium, Doppler Effect, period, wave speed.

2. Do all waves transfer energy? How did you determine the answer?

3. Write the equations for frequency, and wavelength. Please solve for each variable.

4. Compare and contrast the characteristics of electromagnetic waves and mechanical waves.

5. Describe how the speed of sound changes as it moves through a solid, liquid, and a gas.

6. Explain how the Doppler Effect affects and individual as a police siren comes toward you and then

passes you.

7. Draw and label a transverse wave and a longitudinal wave.

SPS10. Students will investigate the properties of electricity and magnetism.

a. Investigate static electricity in terms of

friction

induction

conduction

The way in which a particle interacts with objects around it depends on its electric charge.

Recall that...

•All matter is made of atoms.

•Every atom has a nucleus which contains protons and neutrons. The protons are positively charged, and the

neutrons have no charge. Thus, the nucleus has an overall positive charge.

•The nucleus is surrounded by negatively charged electrons.

•Electrons have a charge of -1.6 x 10-19 coulombs (C).

Static electricity is the buildup of charged, nonmoving particles in an object.

If there is a sudden loss of static electricity, there will be an electric discharge (e.g. lightning).

Static charges can also affect objects, such as hair. If you are wearing a wool hat, for example, and you

remove the hat, the hat rubs against your hair which causes electrons to be transferred from your hair to the

hat. The removal of electrons from your hair causes each hair to gain a slight positive charge. Since similar

charges are repelled by each other, each positively charged hair tries to get away from the other hairs on your

head. To do this, they must stand up and away from the other hairs.

When charged particles come together, they exert a force.

If the charged particles are pulled closer together, there is a force of attraction.

Opposite charges (+ and -) are attracted to each other.

If the charged particles are pushed apart, there is a force of repulsion.

Like charges (+ and + or - and -) repel each other.

If there are an equal number of positive and negative charges, there will be no net charge (the object will be

neutral), and the object will feel neither attraction nor repulsion toward another object. If a charged object is

brought near a neutral object, it is possible for the neutral object's electrons to rearrange their positions and

become charged.

There are three main methods that may be used to charge an object:

1. Friction when two neutral objects made from different materials are rubbed together, the object with the

greater electron affinity takes electrons away from the other object and becomes negatively charged

2. Conduction when a charged object touches a neutral object, electrons can flow between them

3. Induction when a charged object gets close to a neutral object, the particles within the neutral object can

rearrange themselves.


b. Explain the flow of electrons in terms of

alternating and direct current.

the relationship among voltage, resistance and current.

simple series and parallel circuits.

Electrical Circuits & Ohm's Law:

Electrons will flow from an area of high concentration (high potential energy)

to an area of low concentration (low potential energy),

but it takes energy to move the electrons.

Some important definitions...

voltage •a measure of the energy available to move electrons

•the greater the voltage, the more electrons that may be moved

•measured in volts (V) using a voltmeter

current •the flow of electrons through a wire

•measured by counting the number of electrons that pass a given point each second

•the greater the current, the greater the flow of electrons

•measured in amperes (A) using an ammeter

resistance •the opposition to the flow of electrons

•often produces heat, light, or mechanical energy as a result

•the longer or thinner the wire or the greater the temperature, the greater the resistance

•measured in ohms (Ω)

Direct Current:

DC electricity is the continuous movement of electrons through a conducting material such as a metal wire.

The electrons move toward a positive (+) potential in the wire.

Alternating Current:

Alternating current (AC) electricity is the type of electricity commonly used in homes and businesses

throughout the world. While direct current (DC) electricity flows in one direction through a wire, AC

electricity alternates its direction in a back-and-forth motion.

Ohm's law shows the relationship between the voltage, current, and resistance.

The formula for Ohm's law is: V = I × R; voltage = current × resistance; (volts = amperes × ohms)

Any path along which electric charge (electrons) can flow is known as a circuit.

An electric circuit usually consists of...

•a source of electrons (e.g. a battery or a generator)

•a load or resistance (i.e. a device that uses the electric energy such as an appliance or a light bulb)

•wires

•a switch to open and close the circuit

A closed path or a complete circuit is needed to maintain a continuous flow of charge.

Series Circuits

•Electric devices form a single pathway for electron flow.

(i.e. all the parts of a series circuit are connected one after another)

•A break anywhere in the path stops the electron flow in the entire circuit.

•The current is equal to the total voltage divided by the total resistance.

I = VTOTAL/RTOTAL

The current remains constant throughout the circuit.

•The total resistance is equal to the sum of individual resistances along the current path.

RTOTAL = R1 + R2 + R3 + ...

•The voltage drop across each device is proportional to its resistance.

V1 = I × R1

•The total voltage is equal to the sum of the voltage drops across the individual resistances.

VTOTAL = V1 + V2 + V3 + ...

Parallel Circuits

•Electric devices form branches, each of which provides a separate path for the flow of electrons.

•If there is a break in one branch, the other branches will still work.

•Since each device in a parallel circuit is directly connected to the source of electrons, the voltage is the same

across each device. The voltage is equal to the product of the total current and the total resistance.

V = ITOTAL × RTOTAL

•The amount of current in each branch is inversely proportional to the resistance of the branch.

I1 = V/R1

The total current is equal to the sum of the currents in the branches.

ITOTAL = I1 + I2 + I3 + ...

•The total resistance of a parallel circuit can be found by using the following formula.

1/RTOTAL = 1/R1 + 1/R2 + 1/R3 + ...


c. Investigate applications of magnetism and/or its relationship to the movement of electrical

charge as it relates to

electromagnets

simple motors

permanent magnets

Electromagnets are magnets powered by an electric current. They consist of a coil of wire. It's often wrapped

around a magnetic core made of iron or some other ferromagnetic material. The electromagnet only emits a

magnetic field when the current is turned on. The magnetic field can be made stronger or weaker, or it can

even be reversed by varying the amount of current that goes through the device.

Electromagnets are primarily used to move things and to store information. They are used to move things

because a magnetic field will physically repel iron and certain other materials. By carefully controlling the

amount of current a magnet receives, an engineer can control how much force the magnet exerts and how

much the target moves. Magnets are used to store information because many materials will absorb and store a

magnetic field. The field can then be read back by a magnetic reader when the information is needed again.

Many mediums--from audiotapes to memory sticks--use magnets in this way.

Simple Motors

Motors convert electrical energy (from a battery or voltage source) into mechanical energy (used to

cause rotation).

SEE ATTACHED COMIC STRIP

Permanent Magnet

A permanent magnet is an object made from a material that is magnetized and creates its own

persistent magnetic field. An everyday example is a refrigerator magnet used to hold notes on a refrigerator

door. Materials that can be magnetized, which are also the ones that are strongly attracted to a magnet, are

called ferromagnetic (or ferrimagnetic). These include iron, nickel, cobalt, some alloys of rare earth metals,

and some naturally occurring minerals such as lodestone. Although ferromagnetic (and ferrimagnetic)

materials are the only ones attracted to a magnet strongly enough to be commonly considered magnetic, all

other substances respond weakly to a magnetic field, by one of several other types of magnetism.


1. Define: Electricity, magnetism, static electricity, friction, induction, conduction, current, alternating

current, direct current, voltage, resistance, simple series circuit, parallel circuit, proton, neutron, electron,

electromagnet, simple motors, permanent magnets.

2. Explain how static electricity is transferred by friction.

3. Explain how static electricity is transferred by Conduction.

4. Explain how static electricity is transferred by Induction.

5. Explain the difference between Alternating and Direct Current. Give one example of where each is found.

6. State Ohm’s Law. Write the equation that supports ohm’s law. Rearrange that equation to find all

variables.

7. Draw and label a Simple series circuit and a Parallel circuit. Make sure you indicate the flow of the

current, Switch, bulbs, and source of energy.

8. Explain how electromagnets are made and how they work.

9. How do simple motors work? Where are they found?

10. What are permanent magnets? Where are they found?

SPS2. Students will explore the nature of matter, its classifications, and its system for naming types

of matter.

Matter is usually defined as anything that has mass and occupies space.

Gases have no defined shape or defined volume, and low density.

Liquids flow and can be poured from one container to another, have an indefinite shape and takes on the

shape of the container.

Solids have a definite volume and have a definite shape.

Plasma – state of matter that has had the electrons stripped away, uncommon on the Earth.

Examples include: Fire is in the Plasma state, Glow around reentry vehicles from space and The Sun

a. Calculate density when given a means to determine a substance’s mass and volume.

Density is the mass of an object divided by its volume.

Density often has units of grams per cubic centimeter (g/cm3).

SPS5. Students will compare and contrast the phases of matter as they relate to atomic and

molecular motion.

a. Compare and contrast the atomic/molecular motion of solids, liquids, gases and plasmas.

Change of State

Changes between liquid and solids:

Melting: changing from a solid to a liquid (ice melting in a glass of iced tea)

Freezing: changing from a liquid to a solid (water turning to ice cubes in the freezer)

Changes between Liquid and a gas:

Vaporization:

Boiling - liquid changes to a gas at or below the surface of the liquid

Evaporation: liquid changing to a gas only at the surface of the liquid (a puddle drying up

in the sun)

Condensation: gas vapor changing to a liquid (rain)

Changes between a solid and a gas:

Sublimation: Changing from a solid directly to a gas (dry ice turns to carbon dioxide, snow

“disappears” w/out melting.

Deposition: Changing directly from a gas to a solid

b. Relate temperature, pressure, and volume of gases to the behavior of gases.

Relating Temperature & Pressure (at a constant volume)

If the temperature increases, the added thermal energy causes the particles to push harder on the inside

surface of the container… this causes the pressure to also go up. If the temperature decreases, the

pressure decreases. Example: leaving a basketball outside on a cold night causes the ball to go flat.

Relating Pressure and Volume (at a constant Temperature)

Boyles Law (Pressure goes up Volume goes down @ constant temperature)

Pressure is inversely proportional to the volume.

BOYLES LAW – As pressure is increased volume will decrease, and conversely; if the pressure is

decreased, the volume will increase.

Relating Volume & Temperature (at a constant Pressure)

Charles Law- As the temperature increases the volume will also increase; conversely, as the temperature

decreases the volume will also decrease.

Charles Law (Temp goes up Volume goes up @ constant pressure)

Temperature is directly proportional to volume.

Graphing Gas Behavior

variable – the factor that can change in an experiment

manipulated variable – (independent variable) one variable that is changed to test the hypothesis

responding variable – (dependent variable) the factor that changes because of the manipulated variable

Name: ________________________ Date:____________ Physical Science Period: ____

Mixed Word Problem Practice

Measurement Symbol Unit

Distance

Time

Velocity

Mass

Acceleration

Weight

Force

Volume

Heat

Specific heat

Temperature

Current

Resistance

Voltage

Energy

Solve the following problems. Show your work with units.

1. During a race, a runner runs at a speed of 6 m/s. 2 seconds later, she is running at a speed of 10 m/s. What

is the runner’s acceleration? Show your work.

2. If you ride your bike at an average speed of 4 km/h and need to travel a total distance of 28 km, how long

will it take you to reach your destination? Show your work.

3. A tow truck exerts a net horizontal force of 1050 N on a 760-kilogram car. What is the acceleration of the

car during this time? Show your work.

4. The mass of a newborn baby is 3.5 kilograms. What is the baby’s weight? (The acceleration due to gravity

at Earth’s surface is 9.8 m/s2.) Show your work.

5. A small engine causes a 0.3-kg model airplane to accelerate at a rate of 11 m/s2. What is the net force on

the model airplane? Show your work.

6. A worker uses a cart to move a load of bricks weighing 680 N a distance of 10 m across a parking lot. If he

pushes the cart with a constant force of 209 N, what amount of work does he do? Show your work.

7. A girl lifts a 160-N load to a height of 1 m in 0.5 s. What power does the girl produce? Show your work.

8. The input force of a pulley system must move 8.0 m to lift a 3000-N engine a distance of 2.0 m. What is

the IMA of the system? Show your work.

9. A 20-N force applied to the handle of a door produces a 44-N output force. What is the AMA of the

handle? Show your work.

10. What is the kinetic energy of a 72.0-kg sky diver falling at a terminal velocity of 79.0 m/s? Show your

work.

11. A 0.47-kg squirrel jumps from a tree branch that is 3.5 m high to the top of a bird feeder that is 1.2 m high.

What is the change in gravitational potential energy of the squirrel? (The acceleration due to gravity is 9.8

m/s2.) Show your work.

12. A small dog is trained to jump straight up a distance of 1.2 m. How much gravitational potential energy

does the 7.2 kg dog need to jump this high? (The acceleration due to gravity is 9.8 m/s2.) Show your work.

13. How many kilojoules of heat must be transferred to a 480-g aluminum pizza pan to raise its temperature

from 22°C to 234°C? The specific heat of aluminum in this temperature range is 0.96 J/g°C. Show your

work.

14. As 390 g of hot milk cools in a mug, it transfers 30,000 J of heat to the environment. What is the

temperature change of the milk? The specific heat of milk is 3.9 J/g°C. Show your work.

15. What is the acceleration of a car that goes from 20 km/h to 100 km/h in 2 hours?

16. An object moves 20 km in 5 h, what is its speed?

17. If the force on an object is 14 N and the object has a mass of 3.5 kg what is its acceleration?

Name: ___________________________ Date: ______________ Period:_______

Physical Science 1st semester Final Exam Review

Unit 3 (Work, Power, & Machines) and Unit 4 (Energy & Heat)

18. Work (write yes or no to indicate if work is done in the following situations)

a. Lifting a book c. Pushing a shopping cart e. pushing on a wall

b. Carrying a book to your desk d. Holding weights over your head f. kicking a ball

19. Work problems (SHOW WORK)

a. How much work is done if 25 N of force is used to move a rock 5 m?

b. How high did you lift your 12 N sister if you did 48 J of work?

c. If 70 J of work is needed to move an object 15 m what is its weight (force)?

20. What can a machine multiply?

21. Mechanical Advantage problems (SHOW WORK)

a. What is the mechanical advantage of a lever if you apply 14 N of force to lift a car that weighs 1400 N?

b. What is the mechanical advantage of a ramp that is 250 m long and 50 m high?

22. What is efficiency?

23. Why is the efficiency of a machine always less than 100 percent?

24. Give 2 examples of each simple machine:

a. Inclined plane

b. Lever

c. Wedge

d. Wheel and axle

e. Screw

f. Pulley

25. What is kinetic energy? (Define and write the formula)

26. What is potential energy? (Define and write the formula)

27. What is the kinetic energy of a 15 kg rock rolling down hill at a 2.5 m/s? (SHOW WORK)

28. What is the potential energy of a 1.25 kg book sitting on a shelf 4.5 meters high if gravity is 9.8 m/s2?

(SHOW WORK)

29. Give 2 examples of each of the following types of energy

a. Chemical:

b. Elastic potential:

c. Thermal:

d. Nuclear:

e. Mechanical:

f. Kinetic:

g. Gravitational potential:

h. Electrical:

30. What does the law of conservation of energy state?

31. When does the kinetic energy of a roller coaster increase the most?

32. Where does a pendulum have the most potential energy? The most kinetic energy?

33. Define heat:

34. Define temperature:

35. As the temperature of an object increases what happens to the thermal energy?

36. The specific heat of copper is 0.385 J/g°C. What is the energy needed to heat 2.75 g of copper from 14°C

to 35 °C?

37. Describe the three ways energy transfers.

a. Conduction

b. Convection

c. Radiation

38. Which method of energy transfer does not need matter?

39. Which method of energy transfer needs matter?

40. Define conductor.

41. Give two example of conductors:

42. Define insulator.

43. Give two examples of insulators:

Name: ___________________________ Date: ______________ Period:_______

Physical Science 1st semester Final Exam Review

Unit 5 (waves) and Unit 6 (electricity and magnetism)

44. Mechanical Waves a. What do all waves transfer?

b. What is a transverse wave?

c. What is a longitudinal wave?

d. What is frequency?

e. What is the unit of frequency?

f. How is amplitude measured?

g. How do you measure wavelength?

h. Where is the crest of a wave?

i. Where is the trough of the wave?

45. Wave Behavior a. Give an example of refraction

b. Give an example of reflection

c. Give an example of diffraction

d. Give an example of constructive interference

e. Give an example of destructive interference

46. Sound a. What medium does sound travel fastest in?

b. What medium does sound travel slowest in?

47. Electromagnetic waves a. How do you find the speed of a wave?

b. Explain light’s wave-particle duality

c. What are the 7 different waves if the electromagnetic spectrum from longest to shortest wavelength.

d. What are the 7 colors of visible light in order from longest to shortest wavelength

e. What electromagnetic wave is used by cell phones?

f. What electromagnetic wave is used to heat up food?

g. What electromagnetic wave is used to keep food warm?

h. What electromagnetic wave is used to treat cancer?

48. Electricity a. What determines the strength of an electric field?

b. What happens if two like charges are brought near each other?

c. What happens if two opposite charges are brought near each other?

d. Describe each of the following ways that charges transfer

A. Induction

B. Contact

C. Friction

e. What is direct current

f. Give an example of where direct current is used

g. What is alternating current

h. Give an example of where alternating current is used

i. What three things affect the resistance of metal wires?

j. What could you do to a wire to reduce resistance?

49. Ohm’s Law (MUST SHOW WORK) a. The current in a microwave is 35.0 amps and the resistance is 14 ohms. What is the voltage?

b. What is the current a lamp that has a resistance of 25 ohms and uses 12 volts?

50. Magnetism a. What happens when two like poles are brought near each other?

b. What happens when two opposite poles are brought near each other?

c. What happens when you break a magnet in half?

d. What is a permanent magnet?

e. What is a temporary magnet

f. What creates a magnetic field?

g. What is a solenoid?

h. What is a generator?

physical science midterm study guide...

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