Question

a body of mass 5 kg is moving with a velocity of 10m/s is brought to rest by applying brakes . Work done by the brakes is?

Answer 1

work done =kinetic energy =1/2mv^2
=1/2×5×100
=250J

Answer 2

here we have to calculate its initial k.e.
1/2*5*10*10
= 250 J