Suppose that a car traveling to the east (+x direction) begins to slow down as it approaches a traffic light. Which statement concerning its acceleration must be correct?
A) Its acceleration is zero.
B) Its acceleration is in the -x direction.
C) Its acceleration is in the +x direction.
D) Its acceleration is decreasing in magnitude as the car slows down.

Question

Quizplus · Accepted Answer

When a car slows down while traveling east (or in the +x direction), its acceleration is opposite to its direction of motion, which means it is in the -x direction. Acceleration is defined as the rate of change of velocity, so if the velocity is decreasing in the +x direction, the acceleration must be in the -x direction.

Suppose That a Car Traveling to the East (+X Direction)