Motion Graphs

Time

Dis

tanc

e

Can you define:• Motion

is a change in position measured by distance and time

• Speedtells us the rate at which an object moves

• Velocitytells the speed and direction of a moving object

• Accelerationtells us the rate speed or direction changes

Distance-Time GraphsD

ista

nce

Time

Time is always plotted on the x-axis. The further to the right, the longer the time from the start.

Distance is plotted on the y-axis. The higher up the graph, the further from the start.

Time

Dis

tanc

e

Time is increasing to the right, but its distance does not change. It is not moving. We say it is AT REST or STATIONARY.

If an object is moving at a constant speed, it means it has the same increase in distance in a given time.

Dis

tanc

e

Time

Time is increasing to the right, and distance is increasing constantly with time. The object moves at a constant speed.

Constant speed is shown by straight lines on a graph.

Let’s look at two moving objects:Both of the lines in the graph show that each object moved the same distance, but the steeper dashed line got there before the other one:

Dis

tanc

e

Time

A steeper line indicates a larger distance moved in a given time. In other words, higher speed.

Both line are straight, so both speeds are constant.

The line on this graph is curving upwards. This shows a increase in speed, since the line is getting steeper:

In other words, in a given time, the distance the object moves is changed (getting larger). It is accelerating.

Dis

tanc

e

Time

Test your understanding• In your notebook title your next page:

Activity 76.5:

Motion Graphs

• Answer the questions on each slide and thoroughly explain each answer.

1. Which of the graphs shows that one of the runners started 10 yards further ahead of the other? Explain your answer.

0 1 2 3 4

40

30

20

10

Time (s)

Dis

tanc

e (y

ds)

0 1 2 3 4

40

30

20

10

Time (s)

Dis

tanc

e (y

ds)

0 1 2 3 4

40

30

20

10

Time (s)

Dis

tanc

e (y

ds)

0 1 2 3 4

40

30

20

10

Time (s)

Dis

tanc

e (y

ds)

A B

C D

0 1 2 3 4

40

30

20

10

Time (s)

Dis

tanc

e (y

ds)

0 1 2 3 4

40

30

20

10

Time (s)

Dis

tanc

e (y

ds)

0 1 2 3 4

40

30

20

10

Time (s)

Dis

tanc

e (y

ds)

0 1 2 3 4

40

30

20

10

Time (s)

Dis

tanc

e (y

ds)

A B

C D

2. In which of the following graphs below are both runners moving at the same speed? Explain your answer

3. The distance-time graphs that follow represent the motion of a car. Match the descriptions with the graphs. Explain your answers. Use the following format:

3a. Graph A matches description ___ because _____.

3b. Graph B matches description ___ because _____.

3c. Graph C matches description ___ because _____.

3d. Graph D matches description ___ because _____.

Dis

tanc

e

Time

Time

Dis

tanc

e

Dis

tanc

e

Time

Dis

tanc

e

Time

3. Descriptions

i. The car is stopped ii. The car is traveling at a constant speed iii. The car is coming back iv. The speed of the car is decreasing

A.

C.

B.

D.

Create a story to go with the following distance vs. time graph

1

2

3

4

5

Time

Dis

tanc

e

0 1 2 3 4 5 6 7

4.

Create a distance vs time graph to go with the following story

You leave your science class to go to the nearest bathroom. Half way there, you realize you forgot the hall pass and you go back to the classroom to retrieve it. Your teacher tells you, you have a total of 5 minutes to go to the restroom and you have already used 1 ½ minutes. You quickly leave again so you can return on time. After taking 2 minutes in the bathroom, you only have 30 seconds left. Luckily, you make it back on time.

5.

How to graph

• Title

• Label axes (include units)

• Choose the value for each unit (square on the graph) that allows you to use as much of the graph as possible.

• Always use a RULER

Choosing the scale on the axes: 15m/3 s40

30

20

10

Time (s)

Dis

tanc

e (m

)

A 0 1 2 3 4

A. Not enough of the y-axis is used.

20

0 2 4 6 8

15

10

5

Time (s)

Dis

tanc

e (m

)

B

B. Not enough of the x-axis is used.

Time (s)

20

15

10

5Dis

tanc

e (m

)

C 0 1 2 3 4

C. Uses as much of the x-axis and y-axis as possible

Homework

• Finish questions 4 and 5 from class work

• Speed Calculation & Graph Practice Problems, 1-3 (4 is extra credit) (Due Wed/Thurs)

• Graphing Quiz (Wed/Thurs)

• Lab Write Up (Thurs/Fri 2/24-25)

• Star Song (3/3-4)

Lab Write Up: Activity 76

• Use format for lab write up (yellow sheet)

• Include Analysis Questions 1-4 after Data

• Conclusion/Results: use RERUNS and write at least one sentence for each part. Do not write in paragraph form.

Example:

R- The purpose of this lab was to….

E- In this experiment…..

Title:

Problem:

Hypothesis:

Materials:

Procedure:

Data:

Analysis 1-4:

Conclusion/Results:

NameDatePeriod