Question

19) 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 in the -x direction.
B) Its acceleration is zero.
Its acceleration is decreasing in magnitude as the car slows down.
D) Its acceleration is in the +x direction.

Answer 1

Answer: C) Its acceleration is decreasing in magnitude as the car slows down.

Step-by-step explanation:

According to the described situation the car's final velocity is less than its initial velocity, this means the car's velocity decreased as it slows down.

On the other hand, acceleration
`a` is defined as the variation of velocity in time:

`a=(\Delta V)/(\Delta t)`

If the car's velocity decreases, its acceleration is negative. Hence, the acceleration is decreasing in magnitude as well.