Question

A car traveling east at 42.4 m/s passes a trooper hiding at the roadside. The driver uniformly reduces his speed to 25.0 m/s in 4.00 s.
(a) What is the magnitude and direction of the car's acceleration as it slows down?

Answer 1

initial velocity = 42.4 m/s
final velocity = 25.0 m/s
time = 4.00s

a =
(final velocity - initial velocity)/time

(25.0m/s - 42.4m/s)/ 4.00 s


'sign' of answer determines direction of acceleration

Answer 2

North