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Test Prep

# Test Prep

### Multiple Choice

#### 3.1Acceleration

1.

Which variable represents displacement?

1. a
2. d
3. t
4. v
2.

If a velocity increases from 0 to 20 m/s in 10 s, what is the average acceleration?

1. 0.5 m/s2
2. 2 m/s2
3. 10 m/s2
4. 30 m/s2

#### 3.2Representing Acceleration with Equations and Graphs

3.

For the motion of a falling object, which graphs are straight lines?

1. Acceleration versus time only
2. Displacement versus time only
3. Displacement versus time and acceleration versus time
4. Velocity versus time and acceleration versus time
4.

A bullet in a gun is accelerated from the firing chamber to the end of the barrel at an average rate of 6.30×105 m/s2 for 8.10×10−4 s. What is the bullet’s final velocity when it leaves the barrel, commonly known as the muzzle velocity?

1. 7.79 m/s
2. 51.0 m/s
3. 510 m/s
4. 1020 m/s

#### 3.1Acceleration

5.

True or False—The vector for a negative acceleration points in the opposite direction when compared to the vector for a positive acceleration.

1. True
2. False
6.
If a car decelerates from $20m/s$ to $15m/s$ in $5s$, what is $Δv$?
1. -5 m/s
2. -1 m/s
3. 1 m/s
4. 5 m/s
7.

How is the vector arrow representing an acceleration of magnitude 3 m/s2 different from the vector arrow representing a negative acceleration of magnitude 3 m/s2?

1. They point in the same direction.
2. They are perpendicular, forming a 90° angle between each other.
3. They point in opposite directions.
4. They are perpendicular, forming a 270° angle between each other.
8.

How long does it take to accelerate from 8.0 m/s to 20.0 m/s at a rate of acceleration of 3.0 m/s2?

1. 0.25 s
2. 4.0 s
3. 9.33 s
4. 36 s

#### 3.2Representing Acceleration with Equations and Graphs

9.

If a plot of displacement versus time is linear, what can be said about the acceleration?

1. Acceleration is 0.
2. Acceleration is a non-zero constant.
3. Acceleration is positive.
4. Acceleration is negative.
10.
Figure 3.16

True or False—The image shows a velocity vs. time graph for a jet car. If you take the slope at any point on the graph, the jet car’s acceleration will be 5.0 m/s2.

1. True
2. False
11.

When plotted on the blank plots, which answer choice would show the motion of an object that has uniformly accelerated from 2 m/s to 8 m/s in 3 s?

Figure 3.17
1. The plot on the left shows a line from (0,2) to (3,8) while the plot on the right shows a line from (0,2) to (3,2).
2. The plot on the left shows a line from (0,2) to (3,8) while the plot on the right shows a line from (0,3) to (3,3).
3. The plot on the left shows a line from (0,8) to (3,2) while the plot on the right shows a line from (0,2) to (3,2).
4. The plot on the left shows a line from (0,8) to (3,2) while the plot on the right shows a line from (0,3) to (3,3).
12.

When is a plot of velocity versus time a straight line and when is it a curved line?

1. It is a straight line when acceleration is changing and is a curved line when acceleration is constant.
2. It is a straight line when acceleration is constant and is a curved line when acceleration is changing.
3. It is a straight line when velocity is constant and is a curved line when velocity is changing.
4. It is a straight line when velocity is changing and is a curved line when velocity is constant.

### Extended Response

#### 3.1Acceleration

13.
A test car carrying a crash test dummy accelerates from $0$ to $30m/s$ and then crashes into a brick wall. Describe the direction of the initial acceleration vector and compare the initial acceleration vector’s magnitude with respect to the crash acceleration magnitude.
1. The direction of the initial acceleration vector will point towards the wall and its magnitude will be less than the acceleration vector of the crash.
2. The direction of the initial acceleration vector will point away from the wall and its magnitude will be less than the vector of the crash.
3. The direction of the initial acceleration vector will point towards the wall and its magnitude will be more than the acceleration vector of the crash.
4. The direction of the initial acceleration vector will point away from the wall and its magnitude will be more than the acceleration vector of the crash.
14.

A car accelerates from rest at a stop sign at a rate of 3.0 m/s2 to a speed of 21.0 m/s, and then immediately begins to decelerate to a stop at the next stop sign at a rate of 4.0 m/s2. How long did it take the car to travel from the first stop sign to the second stop sign? Show your work.

1. 1.7 seconds
2. 5.3 seconds
3. 7.0 seconds
4. 12 seconds

#### 3.2Representing Acceleration with Equations and Graphs

15.

True or False—Consider an object moving with constant acceleration. The plot of displacement versus time for such motion is a curved line while the plot of displacement versus time squared is a straight line.

1. True
2. False
16.
You throw a ball straight up with an initial velocity of 15.0 m/s. It passes a tree branch on the way up at a height of 7.00 m. How much additional time will pass before the ball passes the tree branch on the way back down?
1. 0.574 s
2. 0.956 s
3. 1.53 s
4. 1.91 s