GUIDE QUESTIONS

Part 1.

1. In part 1, should the work done be increasing every trial?

Explain

No, because based from the data that we’ve gathered the

work is directly proportional to the force applied by the fan.

Another thing is the work is directly proportional to the

displacement of the fan cart. Since our group decreases the

displacement by 10 cm or .10 m for every trial while the cart

is at constant velocity, the time intervened also decreases.

So therefore, the work done should be decreasing in every

trial.

2. In part 1, should the power expended be increasing every

trial?

No, I guess the power expended must be constant in every

trial since the battery supplies the energy to the fan cart.

Since the results that our group had calculated have a very

small difference in each trial, it is safe to say that the power

consumed is constant.

Part 2.

1. In figure 6, why is it incorrect to calculate the work done by

multiplying the spring balance reading F and the horizontal

displacement x?

It is incorrect to calculate the work done by multiplying the

spring balance reading F and the horizontal displacement

because the height of the string is increasing. It will give you

wrong results if you multiply F with the horizontal

displacement because that formula (W=Fx) is only used

when the force and the displacement have the same

direction.

ANALYSIS

1. In table 1, is the work done by the fan cart constant?

Why or why not?

No, the work done by the fan cart not constant

because the force of the fan cart is constant and

when the force of the fan cart is constant and the

displacement increases, the work done also

increases.

2. In table 1, is the power expended by the fan cart

constant? Why or why not?

Yes, the power consumed by the fan cart is constant

because the battery is the one supplying the energy

to the fan cart.

3. In table 2, how does the work done compare with the

increase in gravitational potential energy? Does your

result agree with theory? Why or why not?

Every time an object is lifted up, its gravitational

potential energy or GPE is increased. The mass is

gently pulled so that the kinetic energy can be taken

as constant which we have exactly did during the

experiment. Hence, the results that we've got agree

with a theory that states that the work done on the

curved path is equal to the change in the GPE

because, the calculated results of the experimental

work done and GPE are almost the same.

CONCLUSION

1. What is the correct relationship between the applied force

and the work done?

The work done is directly proportional to the applied force

because as the applied force increases, the work done

also increases if and only if the given displacement is

constant.

2. What is the correct relationship between the displacement

and the work done?

The work done is directly proportional to the direction of

displacement. Since work is equal to the force multiplied

by the displacement, we can conclude that as the

displacement is increased given the force is constant, the

work done also increases.

3. What is the correct relationship between the work done and

the power expended?

The power expended is directly proportional to the work

done because the power is equal to work over time.

RELATED RESEARCH

Work can be defined as transfer of energy. In physics we say that

work is done on an object when you transfer energy to that

object. If one object transfers (gives) energy to a second object,

then the first object does work on the second object.

Work is the application of a force over a distance. Lifting a weight

from the ground and putting it on a shelf is a good example of

work. The force is equal to the weight of the object, and the

distance is equal to the height of the shelf (W= Fxd).

Work-Energy Principle --The change in the kinetic energy of an

object is equal to the net work done on the object.

Energy can be defined as the capacity for doing work. The

simplest case of mechanical work is when an object is standing

still and we force it to move. The energy of a moving object is

called kinetic energy. For an object of mass m, moving with

velocity of magnitude v, this energy can be calculated from the

formula E= 1/2 mv^2.

Types of Energy

There are two types of energy in many forms:

Kinetic Energy   = Energy of Motion

Potential Energy = Stored Energy

Forms of Energy

Solar Radiation -- Infrared Heat, Radio Waves, Gamma Rays,

Microwaves, Ultraviolet Light

Atomic/Nuclear Energy -energy released in nuclear reactions.

When a neutron splits an atom's nucleus into smaller pieces it is

called fission. When two nuclei are joined together under millions

of degrees of heat it is called fusion

Electrical Energy --The generation or use of electric power over a

period of time expressed in kilowatt-hours (kWh), megawatt-hours

(NM) or gigawatt-hours (GWh).

Chemical Energy --Chemical energy is a form of potential energy

related to the breaking and forming of chemical bonds. It is stored

in food, fuels and batteries, and is released as other forms of

energy during chemical reactions.

Mechanical Energy -- Energy of the moving parts of a machine.

Also refers to movements in humans

Heat Energy -- a form of energy that is transferred by a difference

in temperature

What is Power

Power is the work done in a unit of time. In other words, power is

a measure of how quickly work can be done. The unit of power is

the Watt = 1 Joule/ 1 second.

One common unit of energy is the kilowatt-hour (kWh). If we are

using one kW of power, a kWh of energy will last one hour.

Calculating Work, Energy and Power

WORK = W=Fd

Because energy is the capacity to do work , we measure energy

and work in the same units (N*m or joules).

POWER (P) is the rate of energy generation (or absorption) over

time:P = E/t

Power's SI unit of measurement is the Watt, representing the

generation or absorption of energy at the rate of 1 Joule/sec.

Power's unit of measurement in the English system is the

horsepower, which is equivalent to 735.7 Watts.

(Source: http://www.edinformatics.com, 2012)