Question

a car of mass 800 kg is travelling with a velocity of 20ms-1 . when brakes are applied , it stops after traveling a distance of 8 meters. find retardation and retarding force?

Answer 1

u : 20 m/s , s: 8m , v:0 , then ,
a = v×v - u×u/2s,
= 0- 400 /2× 8
= -25 m/s2
f = ma
= 800 × -25
= - 20000N