Question

A motor vehicle of mass 2540kg is travelling at a speed of 108km/h. Calculate the necessary force that will slow it to 36km/h in 0.1 minutes.

Answer 1

Answer:

force = mass * acceleration

also, force = rate of change of momentum

rate of change of momentum = (mv - mu)/t

therefore f = m (v - u)/t

u = 108 km/hr = 108 * 5/18 = 6*5 = 30 m/sec

v = 36 km/sec = 36 *5/18 = 2*5 = 10 m/sec

t = 0.1 min = 6 sec

=> f = 2450 ( 10 - 30)/6

=> f = 2450 * (-20)/6

=> - 8,166.7 N ( retarding force )