Question

What average force magnitude is required to stop a 15,000 kg train in 12.1 s if the train is traveling at 86 km/hr

Answer 1

Step-by-step explanation:

Givens

m = 15000 kg

t = 12.1 seconds

vi = 86 km / hr

vf =0

Formula

F = m*a

a = (vf - vi)/ t

vi has to be converted to m/s

86 km/hr [1000 m / 1 km] * [1 hour / 3600 seconds]

86 * 1000 / 3600 = 23.89 m/s

Solution

a = (vf - vi) / t

a = (0 - 23.89)/12.1

a = - 1.97 m/s^2 The minus means that the trains is slowing down.

F = 15000 kg * - 1.97 m/s^2

F = -29615.7 Newtons.