Question

Certain force acting on a 20 kg mass changes its velocity from 5 ms-1 to 2 ms-1. Calculate the work done by the force.

Answer 1

The Answer Is 210 J

As we know that;

Workdone= Change in Energy

So

W= (K.E)f -(K.E)i

=1/2mv2^2 -1/2mv1^2

= 1/2m(v2_v1)^2

put values

W= 1/2×20(2^2_5^2)

W= 1/2×20×_21

W= 210J