The engine of a locomotive exerts a constant force of 6.5 105 N to accelerate a train to 90 km/h. Determine the time taken for the train of mass 1.8 107 kg to reach this speed from rest.

Answer 1

6.5 * 10^5 I expect you mean and 1.8*10^7

F = m a
6.5 * 10^5 = 1.8*10^7 a

a = 3.61*10^-2 m/s^2

90 km/h (1 h/3600s)(1000 m/km)
= 25 m/s

v = a t
25 = 3.61*10^-2 t

t = 6.93 *10^2 s = 693 s = 11.5 min