Question

a bus of mass 10000kg is moving with a velocity of 90 km per hour calculate the work done to stop the bus???​

Answer 1

Answer:

Here, initial velocity u= 90 km/ hour = 90000/ 3600 = 900/ 36 = 100 /4 = 25m/s

using  v= u + at we have

0 = 25 + at

or a = -25 / t

using s = ut + 1/2at^2 we have

s = 25t + 1/2 (-25 /t) t^2

s= 25t  -  12.5 t = 12.5t

now force f = ma = m (25/t)

work W = f.s = (-25m / t) (12.5t) = -25 * 12.5 *10000 = -25 * 125000 = -3125000J = -3.125 MJ

Explanation: