What is the shape of the graph between speed and kinetic energy of a body?

$A$ particle of mass $m_1$ is moving with a velocity $v_1$ and another particle of mass $m_2$ is moving with a velocity $v_2$. Both of them have the same momentum,but their kinetic energies are $E_1$ and $E_2$ respectively. If $m_1 > m_2$,then:

When the speed of a vehicle increases by $2 \ m/s$,its kinetic energy doubles. What is the original speed of the vehicle?

$A$ boy is rolling a $0.5\, kg$ ball on a frictionless floor with a speed of $20\, ms^{-1}$. The ball gets deflected by an obstacle on the way. After deflection,it moves with $5\%$ of its initial kinetic energy. What is the speed of the ball now? (in $ms^{-1}$)

If the momentum increases by $0.01\%$,what is the percentage increase in kinetic energy (in $\%$)?

$A$ body of mass $8\,kg$ and another of mass $2\,kg$ are moving with equal kinetic energy. The ratio of their respective momenta will be.