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Short Answer

Short Answer

3.1 Acceleration

21.

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
22 .
If a car decelerates from 20 m/s to 15 m/s in 5 s , what is Δ v ?
  1. –5 m/s
  2. –1 m/s
  3. 1 m/s
  4. 5 m/s
23.

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.
24.

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

3.2 Representing Acceleration with Equations and Graphs

25.

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.
26.
A graph titled velocity vs. time plots time (s) on the x axis and velocity (m/s) on the y-axis. At time zero, the velocity is about 15 meters per second. The line extends at a constant rate and reaches a velocity of 170 at a time of 30 seconds.

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
27.

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?

Two blank graphs are shown. The horizontal axis of graph a is labeled “Time, s” and is numbered from 0 to 4 in increments of 1. The vertical axis of graph a is labeled “Velocity, m/s” and is numbered from 0 to 8 in increments of 2. The horizontal axis of graph b is labeled “Time, s” and is numbered from 0 to 4 in increments of 1. The vertical axis of graph b is labeled “Acceleration, m/s^2” and is numbered from 0 to 4 in increments of 1.
  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).
28.

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.