Force acting on a particle moving in a straight line varies with the velocity of the particle as $F = \frac{K}{\upsilon }$  where $K$ is a constant. The work done by this force in time $t$ is

$2$ particles of mass $1\,Kg$ and $5\,kg$ have same momentum, calculate ratio of their $K.E.$

Two identical particles are moving with same velocity $v$ as shown in figure. If the  collision is completely inelastic then

If the potential energy of a gas molecule is $U = \frac{M}{{{r^6}}} - \frac{N}{{{r^{12}}}},M$ and $N$ being positive constants, then the potential energy at equilibrium must be

A wooden block of mass $M$  is suspended by a cord and is at rest. A bullet of mass $m,$ moving with a velocity $v$ passes through the block and comes out with a velocity $v/2$  in the same direction. If there is no loss in kinetic energy, then upto what height the block will rise

A body of mass  $M$  is dropped from a height  $h$  on a sand floor. If the body penetrates $x\,\,cm$  into the sand, the average resistance offered by the sand of the body is