Question

a truck of mass 1800kg is moving with a speed 54km/h. when brakes are applied, it stops with uniform negative acceleration at a distance of 200m. calculate the force applied by the brakes of the truck and the work done before stopping.

Answer 1

here is your answer.
it may help you to understand it.

Answer 2

m=1800 kg

u = 54 kmph = 15 m/s

v=0  

s=200 m

a=v²-u²/2s

a=0-225/400

a=-0.5625m/s²

f=ma

f=1800*-0.5625

f=1012.5 N

w=fs

w=1012.5*200

w=202500 J