Question

What will be the value of the kinetic energy(ek) of a moving body with mass m,if its speed is doubled from v to 2v?

Answer 1

kinetic energy is directly proportional to v^2

coz mass is constant

so new kinetic energy changes as (2v)^2 =4v^2

so kinetic energy increases 4 times

Answer 2

See know that kinetic energy KE=mv²/2

Now, if mass is m and v is doubled to 2v, from the equation, we get

KÉ=m(2v)²/2

=m4v²/2

Dividing this equation by the first one, we get

4. This implies that the ratio is 4:1. Hence, the kinetic energy has been increased by 4 times its original value.