Question

question 7 (1 point) in which one of the following situations does the car have an acceleration that is directed due north? a) a car is traveling southward as its speed decreases from 24 m/s to 18 m/s. b) a car travels southward with a constant speed of 24 m/s. c) a car is traveling southward as its speed increases from 24 m/s to 33 m/s. d) a car is traveling northward as its speed decreases from 24 m/s to 18 m/s. e) a car travels northward with a constant speed of 24 m/s.

Explanation:

Step1: Recall Acceleration Direction

Acceleration is the rate of change of velocity. If velocity and acceleration are in opposite directions, it's deceleration (speed decreasing); same direction, it's speeding up. The direction of acceleration depends on the change in velocity.

Step2: Analyze Option a

Car travels southward (velocity direction south) and speed decreases. So, the change in velocity is opposite to the direction of motion. So acceleration is northward (since it's slowing down while moving south, the acceleration opposes the motion, i.e., north).

Step3: Analyze Option b

Constant speed means acceleration is zero (no change in velocity), so no acceleration direction. Eliminate.

Step4: Analyze Option c

Car travels southward and speed increases. So acceleration is in the same direction as motion (south), so acceleration southward. Eliminate.

Step5: Analyze Option d

Car travels northward and speed decreases. So acceleration is opposite to motion (southward), since it's slowing down while moving north. Eliminate.

Step6: Analyze Option e

Constant speed, so acceleration is zero. Eliminate.

Answer:

a) A car is traveling southward as its speed decreases from 24 m/s to 18 m/s.