Work done by the frictional force is
Negative
Positive
Zero
All of the above
Two identical particles are moving with same velocity $v$ as shown in figure. If the collision is completely inelastic then
A particle of mass $m$ strikes the ground inelastically, with coefficient of restitution $e$
A particle of mass $m$ is moving in a circular path of constant radius $r$ such that its centripetal acceleration $a_c$ is varying with time $t$ as, $a_c = k^2rt^2$, The power delivered to the particle by the forces acting on it is
A bullet of mass $m$ moving with velocity $v$ strikes a suspended wooden block of mass $M$. If the block rises to a height $h$, the initial velocity of the bullet will be
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