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

It is found that when a man increases his speed by "2m/s" ,his kinetic energy is doubled. His original speed was ?

A man increases his speed to 7/5times of his original speed and reaches his office 20 min before to fixed time, then find the usual time taken by him?

A running man has half the KE that a body of half his mass has. The man speeds up by 1.0ms^(-1) and then has the same energy as the boy. What were the original speeds of the man and the boy?

A running man has half the KE that a body of half his mass has. The man speeds up by 1.0ms^(-1) and then has the same energy as the boy. What were the original speeds of the man and the boy?

A man who is running has half the kinetic energy of a boy of half his mass. The man speeds up by 1 ms^(-1) and then has the same kinetic energy as the boy. The original speeds of the man and the boy was: