Two masses of $1 \,g$ and $4 \,g$ are moving with equal kinetic energies. The ratio of the magnitudes of their linear momenta is

$A$ 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 initial speed of the boy is

$A$ 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:

The kinetic energy of a body moving along a straight line varies with time as shown in the figure. The force acting on the body is:

$A$ 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.

The kinetic energy of a car is doubled when its velocity is increased by $1 \,m/s$. Then the initial velocity of the car is