https://www.pinterest.com/pin/290130400973449372/

Lab Report Due Friday

Any questions on the report?

A Graphs of Motion

Update Your TOC

Video

https://www.youtube.com/watch

?v=x2ve5yucNPQ

https://www.youtube.com/watch

?v=ohYQMEhl5Cc

Parts of a Graph

X-axis

Y-axis

All axes must be labeled with

appropriate units, and values.

Position vs. Time

The x-axis is always “time”

The y-axis is always “position/distance”

The slope of the line indicates the velocity of the object.

Slope = (y2-y1)/(x2-x1)

d1-d0/t1-t0

Δd/Δt Velocity = distance

time

Position vs. Time

0

2

4

6

8

10

12

14

16

18

20

1 2 3 4 5 6 7 8 9 10

Time (s)

Po

siti

on

(m

)

Uniform Motion

Uniform motion: equal displacements

occurring during continuous equal time

periods (constant velocity)

Straight lines on position-time graphs mean

uniform motion.

Acceleration/Velocity

Acceleration: rate of which an object changes its speed

(changing how fast an object is moving)

An object is accelerating if its speed or direction is

changing

A= change in velocity Δv

change in time Δt

Velocity is the how fast it’s moving. It is measured in m/s.

Acceleration

If an object is not changing its velocity (how

fast it’s moving), then the object is not

accelerating.

Acceleration The data at the right are

representative of a northward-moving

accelerating object.

The velocity is changing over the

course of time.

In fact, the velocity is changing by a

constant amount - 10 m/s - in each

second of time.

Anytime an object's velocity is

changing, the object is said to be

accelerating; it has an acceleration.

http://www.physicsclassroom.com/mmedia/kinema/acceln.cfm

http://www.physicsclassroom.com/mmedia/kinema/acceln.cfm

Which car or cars (red, green, and/or blue) are

undergoing an acceleration? Study each car individually

in order to determine the answer. (write it in your NB)

If you inspect each car individually, you will more likely notice that only the green

and the blue cars accelerate. The red car moves with a constant speed, covering

the same distance in each second of the animation.

The green and the blue cars are speeding up, thus covering an increasing distance

in each second of the animation.

http://www.physicsclassroom.com/mmedia/kinema/acceln.cfm

Watch the changing of each car(s) velocities. Which is

slower change? Which is a faster change? Which has no

change?

The red car is moving with a constant velocity

The green car has a more gradually changing velocity

The blue car has a faster changing velocity

Check with your partner

Talk to your neighbor

Explain to them what speed, velocity, and acceleration are

Write down in your notebook the similarities and the differences

Speed

VelocityAcceleration

http://www.physicsclassroom.com/mmedia/kinema/acceln.cfm

Consider the position-time graph at the

right. Each one of the three lines on the

position-time graph corresponds to the

motion of one of the three cars. Match the

appropriate line to the particular color of

car.

http://www.physicsclassroom.com/mmedia/kinema/acceln.cfm

The red car is moving with a constant velocity and must correspond to object B which has a constant slope.

The green and blue cars have a changing velocity and must

correspond to lines with a changing slopes - objects A and C. The

green car is object C which has a more gradually changing slope

than object A (blue car).

Steepness of slope on Position-Time

graph

Slope is related to velocity

Steep slope = higher velocity

Shallow slope = less velocity

Positive and Negative Acceleration

increase in speed: positive acceleration

decrease in speed: negative

acceleration.

Velocity vs. Time

X-axis is the “time”

Y-axis is the “velocity”

Slope of the line = the

acceleration

Velocity vs. Time

0

2

4

6

8

10

12

14

16

18

20

1 2 3 4 5 6 7 8 9 10

Time (s)V

elc

oit

y (

m/s

)

Velocity vs. Time

Horizontal lines = constant velocity

Sloped line = changing velocity

Steeper = greater change in velocity per

second

Negative slope = deceleration

Different Velocity-time graphs

Constant velocity?

Acceleration?

Deceleration?

Different Velocity-time graphs

Constant velocity?

Acceleration?

Deceleration?

Different Velocity-time graphs

Velocity vs. Time

0

5

10

15

20

1 2 3 4 5 6 7 8 9 10

Time (s)

Velo

cit

y (

m/s

)

Velocity vs. Time

0

5

10

15

20

25

1 2 3 4 5 6 7 8 9 10

Time (s)

Velo

cit

y (

m/s

)

Acceleration vs. Time

Time is on the x-axis

Acceleration is on the

y-axis

Shows how

acceleration changes

over a period of time.

Often a horizontal line.

Acceleration vs. Time

0

2

4

6

8

10

12

1 2 3 4 5 6 7 8 9 10

Time (s)A

ccele

ra

tio

n (

m/s

^2

)

Constant Rightward Velocity

Constant Leftward Velocity

Constant Rightward Acceleration

Constant Leftward Acceleration

Leftward Velocity with Rightward

Acceleration

Practical Application Velocity/Position/Time

equations

Calculation of arrival times/schedules of aircraft/trains (including vectors)

GPS technology (arrival time of signal/distance to satellite)

Military targeting/delivery

Calculation of Mass movement (glaciers/faults)

Ultrasound (speed of sound) (babies/concrete/metals) Sonar (Sound Navigation and Ranging)

Auto accident reconstruction

Explosives (rate of burn/expansion rates/timing with det. cord)

Free Fall

Recognize the meaning of the acceleration due to gravity

Define the magnitude of the acceleration due to gravity as a positive quantity and determine the sign of the acceleration relative to the chosen coordinate system

Use the motion equations to solve problems involving freely falling objects

Freefall

Defined as the motion of an object if

the only force acting on it is gravity.No friction, no air resistance, no drag

Acceleration Due to Gravity

Galileo Galilei recognized

about 400 years ago that, to

understand the motion of

falling objects, the effects of

air or water would have to be

ignored.

As a result, we will investigate

falling, but only as a result of

one force, gravity.Galileo Galilei 1564-1642

Weknowmemes.com

Galileo’s Ramps

Because gravity causes objects

to move very fast, and because

the time-keepers available to

Galileo were limited, Galileo

used ramps with moveable bells

to “slow down” falling objects for

accurate timing.