A bullet weighing $10 \,g$ and moving with a velocity $300 \,m / s$ strikes a $5 \,kg$ block of ice and drop dead. The ice block is kept on smooth surface. The speed of the block after the collision is ........ $cm / s$

A particle of mass $m$ moving horizontally with $v_0$ strikes $a$ smooth wedge of mass $M$, as shown in figure. After collision, the ball starts moving up the inclined face of the wedge and rises to $a$ height $h$. Suppose the particle when reaches the horizontal surfaces, its velocity with respect to ground is $v_1$ and that of wedge is $v_2$. Choose the correct statement(s)

A ball is dropped from height $10 \,m$. Ball is embedded in sand $1 \,m$ and stops, then

In the figure shown, a particle is released from the position $A$ on a smooth track. When the particle reaches at $B$, then normal reaction on it by the track is .........

A projectile is moving at $20\,m/sec$ at its highest point where it breaks into two equal parts due to an internal explosion. One part moves vertically up at $30\,m/sec$ . Then the other part will move at ............. $\mathrm{m}/ \mathrm{s}$

A body falls towards earth in air. Will its total mechanical energy be conserved during the fall ? Justify.