Physics Sec. 2.2 Acceleration

1. The average acceleration is the ratio of which of the following quantities? 

• 
  

  $\Delta$ d
  

• $\Delta$ v

• v: $\Delta$ v

• $\Delta$ v: $\Delta$ t

The speed of a car will increase if the car’s

• initial velocity is positive and its acceleration is zero.

• initial velocity is positive and its acceleration is positive.

• initial velocity is positive and its acceleration is negative.

• initial velocity is negative and its acceleration is positive.

For a scooter with a negative acceleration, which of the following statements is always true?

• The scooter is losing speed.

• The final velocity of the scooter will be negative.

• The initial velocity of the scooter will be greater than its final velocity.

• The scooter will have a negative displacement.

Questions 4–9 refer to the following velocity-time graph of a jogger. The positive direction is away from the jogger’s home.

The jogger is at rest during which interval?

• AB

• BC

• DE

• EF

During which of the following intervals does the jogger have a constant positive velocity?

• BC

• CD

• DE

• FG

During which interval is the magnitude of the jogger’s acceleration the greatest?

• AB

• BC

• DE

• EF

During which of the following intervals is the speed of the jogger decreasing?

• AB only

• AB and CD

• AB, CD, and EF

• EF only

During which of the following intervals is the jogger’s motion toward home?

• CD and EF

• DE only

• EF only

• EF and FG

Rank the four displacements for the time intervals CD, DE, EF, and FG in decreasing order. Explain your answer.

A cat walking at 0.25 m/s sees a mouse and accelerates uniformly at 0.40 m/s2 for 3.0 s. What is the cat’s displacement during this time?