Starting from Rest, a Car Accelerates Down a Straight Road

question 31

Multiple Choice

Starting from rest, a car accelerates down a straight road with constant acceleration a for a time t, then the direction of the acceleration is reversed, i.e., it is -a, and the car comes to a stop in an additional time t, the time for the whole trip being 2t. At what time, or times, is the average velocity of the car for the trip equal to its instantaneous velocity during the trip?

• A) There is no such time.
• B) It is at the halfway point at t.
• C) This occurs at 2 times, at 0.5 t and 1.5 t.
• D) This occurs at 2 times, at 0.707 t and 1.293 t.