Motion Graphs Practice

Motion Graphs

Describing the motion of an object is occasionally hard to do with words. Sometimes

graphs help make motion easier to picture, and therefore understand.

Motion Graphs

Remember:

• Motion is a change in position measured by distance and time.

• Speed tells us the rate at which an object moves.

• Velocity tells the speed and direction of a moving object.

• Acceleration tells us the rate speed or direction changes.

Motion Graphs

DISTANCE-TIME GRAPHS

Plotting distance against time can tell you a lot about motion. Let's look at the axes:

Time is always plotted on the X-axis (bottom of the graph). The further to the right on the axis, the longer the time from the start. Distance is plotted on the Y-axis (side of the graph). The higher up the graph, the further from the start.

Motion Graphs

DISTANCE-TIME GRAPHS

If an object is not moving, a horizontal line is shown on a distance-time graph.

Time is increasing to the right, but its distance does not change. It is not moving. We say it is At Rest.

Motion Graphs

DISTANCE-TIME GRAPHS

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

Motion Graphs

DISTANCE-TIME GRAPHS

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:

A steeper line indicates a larger distance moved in a given time. In other words, higher speed. Both lines are straight, so both speeds are constant.

Motion Graphs

DISTANCE-TIME GRAPHS

Graphs that show acceleration look different from those that show constant speed.

The line on this graph is curving upwards. This shows an increase in speed, since the line is getting steeper: In other words, in a given time, the distance the object moves is change (getting larger). It is accelerating.

Motion Graphs

DISTANCE-TIME GRAPHS

Summary:

A distance-time graph tells us how far an object has moved with time.

• The steeper the graph, the faster the motion.

• A horizontal line means the object is not changing its position - it is not moving, it is at rest.

• A downward sloping line means the object is returning to the start.

Motion Graphs

SPEED-TIME GRAPHS

Speed-Time graphs are also called Velocity-Time graphs.

Speed-Time graphs look much like Distance-Time graphs. Be sure to read the labels!! Time is plotted on the X-axis. Speed or

velocity is plotted on the Y-axis. A straight horizontal line on a speed-time graph means that speed is constant. It is not changing over time. A straight line does not mean that the

object is not moving!

Motion Graphs

SPEED-TIME GRAPHS

This graph shows increasing speed. The moving object is accelerating.

Motion Graphs

SPEED-TIME GRAPHS

This graph shows decreasing speed. The moving object is decelerating.

Motion Graphs

SPEED-TIME GRAPHS

What about comparing two moving objects at the same time?

Both the dashed and solid line show increasing speed. Both lines reach the same top speed, but the solid one takes longer. The dashed line shows a greater acceleration.

Motion Graphs

SPEED-TIME GRAPHS

Summary:

A speed - time graph shows us how the speed of a moving object changes with time.

• The steeper the graph, the greater the acceleration.

• A horizontal line means the object is moving at a constant

speed.

• A downward sloping line means the object is slowing down.

Multiple Choice

Which of the graphs shows that one of the runners started 10 yards further ahead of the other?

Multiple Choice

In which of the following graphs below are both runners moving at the same speed?

Multiple Choice

Graph A shows _____

• the car is stopped.

• the car is traveling at a constant speed away from a starting point.

• the speed of the car is decreasing.

• the car is coming back to a .

Multiple Choice

Graph B shows _____

• the car is stopped.

• the speed of the car is increasing.

• the speed of the car is decreasing.

• the car is traveling at a constant speed returning to a starting spot.

Multiple Choice

Graph C shows _____

• the car is stopped.

• the car is traveling at a constant speed.

• the speed of the car is decreasing.

• the car is coming back.

Multiple Choice

Graph D shows _____

• the car is stopped.

• the car is traveling at a constant speed.

• the speed of the car is decreasing.

• the car is coming back.

Multiple Choice

Graph E shows _____

• the car is stopped.

• the car is traveling at a constant speed.

• the car is speeding up.

• the car is slowing down

Multiple Choice

Graph F shows _____

• the car is stopped.

• not enough information to tell.

• the car is accelerating.

• the car is slowing down

Multiple Choice

Graph G shows _____

• the car is stopped.

• the car is traveling at a constant speed.

• the car is accelerating.

• the car is slowing down

Multiple Choice

Graph H shows _____

• the car is stopped.

• the car is traveling at a constant speed.

• the car is accelerating.

• the car is slowing down

Multiple Choice

Look at the graph above. It shows how three runners ran a 100-meter race.

Which runner won the race?

• Albert

• Bob

• Charlie

Multiple Choice

Look at the graph above. It shows how three runners ran a 100-meter race.

Which runner stopped for a rest?

• Albert

• Bob

• Charlie

Multiple Choice

Look at the graph above. It shows how three runners ran a 100-meter race.

How long did the runner stop?

• 5 seconds

• 14 seconds

• 8 seconds

• 13 seconds

Multiple Choice

Look at the graph above. It shows how three runners ran a 100-meter race.

How long did Bob take to complete the race?

• 5 seconds

• 14 seconds

• 12 seconds

• 17 seconds

Multiple Choice

Look at the graph above. It shows how three runners ran a 100-meter race.

Calculate Albert’s average speed.

• 8.3 m/s

• 7.1 m/s

• 5.8 m/s

• 10.4 m/s

Multiple Choice

The graph shows how the speed of a bus changes during part of a journey. Choose the correct word from the following list to describe the motion during each

segment of the journey.

Segment 0-A:

The bus is _____.

• accelerating

• decelerating

• moving at a constant speed

• at rest

Multiple Choice

The graph shows how the speed of a bus changes during part of a journey. Choose the correct word from the following list to describe the motion during each

segment of the journey.

Segment A-B:

The bus is _____

• accelerating

• decelerating

• moving at a constant speed

• at rest

Multiple Choice

The graph shows how the speed of a bus changes during part of a journey. Choose the correct word from the following list to describe the motion during each segment of the journey.

Segment B-C:

The bus is______

• accelerating

• decelerating

• moving at a constant speed

• at rest

Multiple Choice

The graph shows how the speed of a bus changes during part of a journey. Choose the correct word from the following list to describe the motion during each segment of the journey.

Segment C-D:

The bus is______

• accelerating

• decelerating

• moving at a constant speed

• at rest

Multiple Choice

The graph shows how the speed of a bus changes during part of a journey. Choose the correct word from the following list to describe the motion during each segment of the journey.

Segment D-E:

The bus is______

• accelerating

• decelerating

• moving at a constant speed

• at rest

Multiple Choice

The graph shows how the speed of a bus changes during part of a journey. Choose the correct word from the following list to describe the motion during each segment of the journey.

Segment E-F:

The bus is______

• accelerating

• decelerating

• moving at a constant speed

• at rest