Question

If a man increse his speed by 2m/s, his J.E. is doubled, the original dpeed of man is :

Answer 1

Let KE is 1/2mv^2.
He increases speed by 2m/s,so new speed will be (v+2)m/s.

So form the equation now,2×1/2mv^2=1/2m(v+2)^2.

Solve it and then cheers.