Question

If a man increases his speed by 2m/s, his K.E. is doubled. What is the original speed of man?

Answer 1

let his speed be x m/s
ke=mx^2/2

new speed=(x+2) m/s

new ke=m(x+2)^2/2

atq,
2mx^2/2=m(x+2)^2/2
2x^2=(x+2)^2