When a $4 \mathrm{kg}$ rifle is fired, the $10 \mathrm{g}$ bullet receives an acceleration of $3\times {10}^6 \mathrm{cm} {\mathrm{s}}^{-2}.$ The magnitude of the force acting on the rifle (in newton) is

In the figure given below, with what acceleration does the block of mass $m$ will move? (Pulley and strings are massless and frictionless)

$T_1$ and $T_2$ in the given figure are

In the arrangement shown, the mass $m$ will ascend with an acceleration (Pulley and rope are massless)

Figure shows a uniform rod of length $30 \mathrm{cm}$ having a mass $3.0 \mathrm{kg}.$ The rod is pulled by constant forces of $20 N$ and $32 N$ as shown. Find the force exerted by $20 \mathrm{cm}$ part of the rod on the $10 \mathrm{cm}$ part (all surfaces are smooth) is