Question

If the mass and velocity will doubled its kinetic energy become

Answer 1

then the kinetic energy becomes 4 times
because kinetic energy is proportional to mass and velocity

Answer 2

Let the initial mass be m and that velocity be v.

Then, initial kinetic energy(E₁) = $1/2 m v^{2}$.

Let the final mass be m' and that velocity be v'.

Then, final kinetic energy(E₂) = 1/2 m'v'²

=1/2 × 2m × (2v)²

=1/2 × 2m × 4v²

=8 × 1/2 mv²

=8 × E₁.

∴ The kinetic energy becomes 8 times when mass and velocity are doubled.