Question

A race car is moving with a velocity of 144 kilometers/hour. The driver applies the brakes, and the car comes to a halt in 12.0 seconds. What is the acceleration of the car after 12.0 seconds?

Answer 1

During the braking, the acceleration is the ratio of the velocity change to the time of braking a = dv/dt = 144 km/hr/12 s. Ideally, you would put this into
consistent units, such as m per s per s: a = 144000m/(3600s)(12s)=3.33m/s^2, about 1/3 the acceleration of gravity, thus g/3.

After the car has stopped in 12s, the acceleration becomes zero, but that would mean this is a trick question.

Answer 2

Well C isnt correct.