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
$Mg\left( {\frac{h}{x}} \right)$
$Mg\left( {1\,+\,\frac{h}{x}} \right)$
$Mgh\,+\,Mgx$
$Mg\left( {1\,-\,\frac{h}{x}} \right)$
A $15\, g$ ball is shot from a spring gun whose spring has a force constant of $600\, N\, m$. The spring is compressed by $3\, cm$. The greatest possible velocity of the ball for this compression is ............. $\mathrm{m}/ \mathrm{s}$ $(g = 10\, m/s^2$)
A particle fall from height $h$ on $a$ static horizontal plane rebounds. If $e$ is coefficient of restitution then before coming to rest the total distance travelled during rebounds will be:-
Two identical balls $A$ and $B$ are released from the positions shown in figure. They collide elastically on horizontal portion $MN$. The ratio of the heights attained by $A$ and $B$ after collision will be (neglect friction)
A particle of mass $7\, kg$ moving at $5\, m/s$ is acted upon by a variable force opposite to its initial direction of motion. The variation of force $F$ is shown as a function of time $t$.
In an elastic collision of two particles the following quantity is conserved