Question: momentum of a body is doubled what is the percentage increase in kinetic energy?
Answer: Kinetic energy of a body of given mass, is directly proportiional to its square of its velocity. When momentum is doubled, mass remaining constant, this means velcity is doubled. Hence, kinetic energy becomes 22=4 times i.e. say from 100 units to 400 units. and percentage increase in kinetic energy is 400−100=300% .