Question

A runaway train takes 12 seconds to stop after the emergency brakes are applied. If the emergency brakes can slow the train at the rate of 0.5 m/s2, how fast was the train going before the brakes were applied?

Answer 1

t=12s
v=0 m/s (Stops)
a=-5 m/s2 (Deceleration)
u=?

v=u+at
0=u-(5*12)
u=5*12
u=60 m/s