Question

multiple select question
select all that apply
in which of the following situations does the car have a nonzero acceleration?

the car is on cruise control traveling around a curve.
the car is traveling at the speed limit, and then it comes to a complete stop in a straight line.
the car is on cruise control traveling in a straight line.
the car starts from rest and speeds up to the speed limit moving in a straight line.
the car is parked.
the car is traveling at the speed limit and then comes to a complete stop while traveling around a curve.

Explanation:

Acceleration is non-zero when an object's speed changes, or its direction of motion changes (since acceleration is a vector quantity).

1. Traveling around a curve on cruise control: Direction changes, so acceleration is non-zero.
2. Coming to a stop in a straight line: Speed decreases, so acceleration is non-zero.
3. Straight line cruise control: Constant speed and direction, acceleration is zero.
4. Speeding up from rest in a straight line: Speed increases, so acceleration is non-zero.
5. Parked: No motion, speed is constant (0), acceleration is zero.
6. Stopping while going around a curve: Speed decreases AND direction changes, so acceleration is non-zero.

Answer:

A. The car is on cruise control traveling around a curve.
B. The car is traveling at the speed limit, and then it comes to a complete stop in a straight line.
D. The car starts from rest and speeds up to the speed limit moving in a straight line.
F. The car is traveling at the speed limit and then comes to a complete stop while traveling around a curve.