Motion Graphs Review

The graph represents the motion of an object. According to the graph, as time increases, the velocity of the object

• decreases

• increases

• remains the same

Answer explanation

Velocity is the slope of the line. Since the slope does not change, the velocity is constant.

The displacement-time graph represents the motion of a cart initially moving forward along a straight line. During which interval is the cart moving forward at constant speed?

• DE

• CD

• AB

• BC

Answer explanation

Constant speed on a d-t graph is a straight line, forward motion is a positive slope. Therefore, it must be BC.

The graph represents the velocity-time relationship for a 2.0-kilogram mass moving along a horizontal frictionless surface. What distance does the mass move during interval EF?

• 6.0 m

• 3.0 m

• 2.0 m

• 1.0 m

Answer explanation

Area under the line gives distance. So (1/2)(3s)(2m/s) = 3m

Tags

NGSS.MS-PS3-1

Which graph best represents the motion of an object whose speed is increasing?

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Answer explanation

Increasing speed means the object is accelerating. On a distance vs. time graph where the slope is the velocity, this is shown by a curved line - which indicates a changing velocity!

Tags

NGSS.HS-PS2-1

Which pair of graphs represents the same motion of an object?

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Answer explanation

Both graphs show the objects accelerating, moving forward.

Tags

NGSS.HS-PS2-1

The diagram represents the relationship between velocity and time of travel for four cars, A, B, C, and D, in straight-line motion. Which car has the greatest acceleration during the time interval 10. seconds to 15 seconds?

• A

• B

• C

• D

Answer explanation

Greatest acceleration on a velocity vs. time graph is the steepest slope.

Tags

NGSS.HS-PS2-1

The graph represents the relationship between speed and time for an object moving along a straight line. What is the total distance traveled by the object during the first 4 seconds?

• 40 m

• 20 m

• 5 m

• 80 m

Answer explanation

Distance is equal to the area uner the graph;

d = 1/2 b x h

d = 1/2 (4sec)(20m/s)

d = 40 m

Tags

NGSS.MS-PS3-1

According to the graph, which quantity related to the motion of the body is constant?

• acceleration

• displacement

• velocity

• speed

Answer explanation

Slope is acceleration and slope is constant

Which graph best represents the motion of a block accelerating uniformly down an inclined plane? (uniformly just means at a constant rate, here - the important word is that it is accelerating)

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Answer explanation

Acceleration on a d-t graph is shown by a curved line

Tags

NGSS.HS-PS2-1

The distance-time graph represents the position of an object moving in a straight line. What is the speed of the object during the time interval t = 2.0 seconds to t = 4.0 seconds?

• 7.5 m/s

• 10 m/s

• 5.0 m/s

• 0.0 m/s

Answer explanation

Find the slope of the line between those two points (30-10m)/(4-2s) = 20m/2s = 10 m/s