Question

A train has a mass of 1.50 x 107 kg. If the engine can

exert a net force of 7.50 x 105 N on the train, how much
time is required for the train to reach a speed of 80.0
km/h, if the train begins from rest?

Answer 1

vi=0, vf=80km/hr=22m/s, m=1.5x107kg, F = 7.5x105N.

a=F/m, t=(vf-vi)/a= (vf-vi)m/F = (22m/s)(1.5x107kg)/7.5x105N = 440 kg m/sN = 440 s or 7mins