Question

) A car is traveling on a straight, horizontal road at 20 m/s when the driver slams on the brakes. The force of friction between the car and the road is 900 N. The mass of the car is 1800 kg.
(a) Make a free body diagram for the car on the set of axes provided.
(b) How far will the car go before stopping?

Answer 1

(b) f = m a ... a = f / m = 900 / 1800
a = .5 m/s^2

so it takes 40 s to stop ... 20 / .5

ave velocity is ... (20 + 0) / 2

distance = v * t