Question

A drivers moving at a constant speed of 30m/s sees an accident up ahead and hits the brakes. if the car decelerates at a constant rate of -5m/s2, how far does the car go before it comes to stop? A.90m B. 100m c. 40m d. 20m

Answer 1

Use v^2 = v0^2 + 2aΔx. With v = 0, v0 = 30 m/s, a = -5 m/s^2:

0 = (30)^2 + 2(-5)Δx → Δx = -900 / (-10) = 90 m.

Answer: A. 90 m.