The kinetic energy $k$ of a particle moving along a circle of radius $R$ depends on the distance covered $s$ as $k = a{s^2}$ where $a$ is a constant. The force acting on the particle is
$2a\frac{{{s^2}}}{R}$
$2as{\left( {1 + \frac{{{s^2}}}{{{R^2}}}} \right)^{1/2}}$
$2as$
$2a\frac{{{R^2}}}{s}$
A force of $5\,N$ acts on a body of mass $5\, kg$ for $1\, second$ and gives it a momentum $p$ and kinetic energy $E$. If the same force accelerates the same body through $1\,m$, the momentum and energy attained by the body are $p’$ and $E’$ respectively. Which of the following relations is correct?
Sand is deposited at a uniform rate of $20\ kg/s$ and with negligible kinetic energy on an empty conveyor belt moving horizontally at a constant speed of $10$ meters per minute. Find the force required to maintain constant velocity of the conveyor belt.
Two bodies $A$ and $B$ having masses in the ratio of $3 : 1$ possess the same kinetic energy. The ratio of their linear momenta is then
The same retarding force is applied to stop a train. The train stops after $80 m$. If the speed is doubled, then the distance will be
A bullet of mass $50 \mathrm{~g}$ is fired with a speed $100 \mathrm{~m} / \mathrm{s}$ on a plywood and emerges with $40 \mathrm{~m} / \mathrm{s}$. The percentage loss of kinetic energy is :