The force constant of a wire is $k$ and that of another wire is $2k$. When both the wires are stretched through same distance, then the work done

 A lorry and a car moving with the same $K.E.$  are brought to rest by applying the same retarding force, then

Two equal masses ${m_1}$ and ${m_2}$ moving along the same straight line with velocities $+ 3 \,m/s$ and $-5\, m/s$ respectively collide elastically. Their velocities after the collision will be respectively

As per the given figure, a small ball $P$ slides down the quadrant of a circle and hits the other ball $Q$ of equal mass which is initially at rest. Neglecting the effect of friction and assume the collision to be elastic, the velocity of ball $Q$ after collision will be $............\,m/s$ $:\left( g =10\,m / s ^2\right)$

$A$ ball strikes a smooth horizontal ground at an angle of $45^o$ with the vertical. What cannot be the possible angle of its velocity with the vertical after the collision ................. $^o$ (Assume $e \leq 1$ ).

Consider elastic collision of a particle of mass $m $ moving with a velocity $u$ with another particle of the same mass at rest. After the collision the projectile and the struck particle move in directions making angles ${\theta _1}$and ${\theta _2}$respectively with the initial direction of motion. The sum of the angles. ${\theta _1} + {\theta _2},$ is......$^o$