http://www.youtube.com/watch?v=MlD5NBnzFhE

JTPS

What are 3 words that come to mind when you think about Motion?

Linear MotionLinear Motion

instantaneous speed - the speed that something has at any one instance

interval timecovered distance total = speed average

timedistance Speed

...or 70 miles/hour on the open road.

However, during this trip your instantaneous speed might have been 0 miles/hour at a stoplight...

1. What is the average speed of a cheetah that sprints 100 meters in 4 seconds?

2. How about if it sprints 50 m in 2 s?

miles/hour…………….mph

kilometer/hour……….km/h

meters/second……….m/s

furlongs/fortnight?

If a car moves with an average speed of 60km/h for an hour, it will travel a distance of 60 km. (a) How far would if travel if it moved at

this rate for 4 hours? (b) For 10 h? (c) Would it be possible for the car to have

an average speed of 60km/h and never exceed a reading of 60km/h?

Velocity = {speed with a direction}

Examples:

70 mph is a speed.

70 mph North is a velocity.

VelocityVelocity

Acceleration - rate of change in velocity due to change in speed or direction

AccelerationAcceleration

interval time velocityof change =on Accelerati

Example:• 9.8 meters/second2 downward

"She moves at a constant speed in a constant direction.”

Say the same sentence in fewer words.

Answer: “She moves at constant velocity.”

The speedometer of a car moving to the east reads 100km/h.

It passes another car that moves to the west at 100km/h.

Do both cars have the same speed?

Do they have the same velocity?

During a certain time, the speedometer of car reads a constant 60km/h.

Does this indicate a constant speed?

Constant velocity?

(a) acceleration and time.(b) velocity and time.(c) distance and time.(d) distance and acceleration.

(a) 10km/h(b) 20km/h(c) 30km/h(d) more than 30km/h

The slope of the distance-time graph is the velocity

Constant Velocity Changing Velocity

Distance VS. Time

The slope of the velocity-time graph is the acceleration.

Constant Acceleration Changing Acceleration

Velocity VS. Time

How To Graphically Represent Linear Motion

Depicting Motion

Coordinate System- Deciding where to place the measuring tape and when to start the timer.

Origin- Point where both variables are of value zero.

Coordinate System

Problem Solving Follow these steps to solve problems:

Read ProblemMake Diagram Identify Knowns Identify UnknownsChoose FormulaSolve (and Check)

Acronym R.D. KUFS (Mr. Hairston’s Rap Alias)

Practice Drawing Motion A bike travels at a constant speed of 4.0

m/s for 5 s. How far does it go?

Practice Drawing Motion A bike accelerates from 0.0 m/s to 4.0

m/s in 4 s. What distance does it travel?

Practice Drawing Motion A bike first accelerates from 0.0 m/s to

5.0 m/s in 4.5s. What is the acceleration of the bike?

A car travels southeast at 83 m/s. How long will it take the car to travel 633 m?

White Board Question

Describing Motion: The Kinematic Equations

DISCOVERING THE UNKNOWN

Kinematic Equations

advv

atvv

tvv

d

attvd

if

if

fi

i

2

2

2

1

22

2

d = displacement

vi = initial velocity

vf = final velocity

a = acceleration

t = time

2

21gtd

A truck having an initial velocity of 30 m/s accelerates uniformly at +3 m/s2.

a)What is its velocity after 4 seconds?

a)How far has it traveled in 4 seconds?

c) How fast is it moving after it has traveled 100 m from its original position?

d)How long did it take to travel the 100 m?

R.D. KUFS

Ima Hurryin is approaching a stoplight moving with a velocity of +30.0 m/s. The light turns yellow, and Ima applies the brakes and skids to a stop. If Ima's acceleration is negative (-)8.00 m/s2, then determine the displacement of the car during the skidding process. (Note that the direction of the velocity and the acceleration vectors are denoted by a (+) and a (–) sign).

56.3 m

Practice Problem Solving

Ben Rushin is waiting at a stoplight. When it finally turns green, Ben accelerated from rest at a rate of a 6.00 m/s2 for a time of 4.10 seconds. Determine the displacement of Ben's car during this time period.

50.4 m

Practice Problem Solving

Free Falling

What will you do when there’s nothing holding you back?

• An object is in free fall when the only force acting on it is the force of gravity

• The force of gravity points downward• Acceleration due to gravity is 9.8m/s2

• Air resistance ignored

Free FallFree Fall

To a physicist, the term "free fall" has a different meaning than it does to a skydiver. In physics, free fall is the (one-dimensional) motion of any object under the influence of gravity only - no air resistance or friction effects of any kind, whereas it is air resistance that makes skydiving a hobby rather than a suicide attempt!

An Object In Free Fall

You should also note that an object doesn't have to be falling to be in free fall - if you throw a ball upward its motion is still considered to be free fall, since it is moving under the influence of gravity. 

An Object In Free Fall

• An object is in free fall when the only force acting on it is the force of gravity

• The force of gravity points downward

• Air resistance ignored

• Acceleration due to the force of gravity near the surface of Earth is downward and has a value of g = 9.8 m/s2

(note: g is just the magnitude of the objects acceleration)

• We have then the conditions of one-dimensional kinematics – straight line motion with constant acceleration.

Free Fall

(a) you drop an object from rest at t=0.

(b) velocity acquired = acceleration time v = g t

(c)

For Free Fall...For Free Fall...

timetimeonAccelerati21 = traveledDistance

2

21gtd

A ball is thrown vertically upward at 10 m/s. How high will it get, how long will it be in the air, and how fast will it be moving when it hits the ground.

Sample Problem

timedistance Speed

Velocity = {speed with a direction}

interval time velocityof change =on Accelerati

g = 9.8 m/s2 downward

Kinematic Equations

advv

atvv

tvv

d

attvd

if

if

fi

i

2

2

2

1

22

2

d = displacement

vi = initial velocity

vf = final velocity

a = acceleration

t = time

v = g t

Free FallFree Fall

2gt

21d