A machine gun has a mass of $20 \mathrm{kg}$. It fires $35 \mathrm{g}$ bullets at the rate of $400$ bullets per minute with a speed of $400 \mathrm{m} {\mathrm{s}}^{-1}$. What average force must be applied to the gun to keep it in position?

A person of mass $M \mathrm{kg}$ is standing on a lift. If the lift moves vertically upwards according to the given $v-t$ graph then find out the weight of man at the following instants: $\left(g=10 \mathrm{m} {\mathrm{s}}^{-2}\right)$ $t=1 \mathrm{second}$

A person of mass $M \mathrm{kg}$ is standing on a lift. If the lift moves vertically upwards according to the given $v-t$ graph, then find out the weight of man at the following instants: $\left(g=10 \mathrm{m} {\mathrm{s}}^{-2}\right)$, $t=8 \mathrm{second}$

A person of mass $M \mathrm{kg}$ is standing on a lift. If the lift moves vertically upwards according to the given $v-t$ graph, then find out the weight of man at the following instants: $\left(g=10 \mathrm{m} {\mathrm{s}}^{-2}\right)$, $t=12 \mathrm{second}$

Calculate $a_{\mathrm{system}}$ corresponding to the following diagram.

Calculate $F_{\mathrm{DE}}$ corresponding to the following diagram.