A ball of mass $m$ is dropped from a heigh $h$ on a platform fixed at the top of a vertical spring, as shown in figure. The platform is depressed by a distance $x.$ Then the spring constant is
$\frac{{mg}}{{(h + x)}}$
$\frac{{mg}}{{(h + 2x)}}$
$\frac{{2mg(h + x)}}{{{x^2}}}$
$\frac{{mg}}{{(2h + x)}}$
In the figure shown the potential energy $(U)$ of a particle is plotted against its position $'x'$ from origin. The particle at
A light and a heavy body have equal kinetic energy. Which one has a greater momentum
A ball moving with velocity $2\, m/s$ collides head-on with another stationary ball of double the mass. If the coefficient of restitution is $0.5$, then their velocities (in $m/s$) after collision will be
The force $F$ acting on a body moving in a circle of radius $r$ is always perpendicular to the instantaneous velocity $v$. The work done by the force on the body in one complete rotation is :
A ball of mass $M$ falls from a height $h$ on a floor which the coefficient of restitution is $e$. The height attained by the ball after two rebounds is