Question

A 10^4 kg train moving at 20m/s stops in a distance of 500m. Calculate the force applied by the train's braking system.

Answer 1

a=(V^2-Vo)/2d = (0-20^2)/1000=-0.4 m/s^2

F = m*a = 10000 * -0.4 = -4,000 N.