Work done by the frictional force is

The linear momentum of a body of mass $8 \ kg$ is $24 \ kg \ m \ s^{-1}$. If a constant force of $24 \ N$ acts on the body in the direction of motion of the body for a time of $3 \ s$,then the increase in the kinetic energy of the body is (in $J$)

$A$ raindrop of mass $1.00 \, g$ falling from a height of $1 \, km$ hits the ground with a speed of $50 \, m s^{-1}$. Calculate
$(a)$ the loss of $PE$ of the drop
$(b)$ the gain in $KE$ of the drop
$(c)$ Is the gain in $KE$ equal to loss of $PE$? If not,why?
Take $g = 10 \, m s^{-2}$.

$A$ particle of mass $m$ is at rest in a train moving with constant velocity with respect to the ground. Now,the particle is accelerated by a constant force $F_0$ acting along the direction of motion of the train for time $t_0$. $A$ girl in the train and a boy on the ground measure the work done by this force. Which of the following are $INCORRECT$?

$A$ circular well of diameter $2 \ m$ has water up to the ground level. If the bottom of the well is at a depth of $14 \ m$,the time taken in seconds to empty the well using a $1.4 \ kW$ motor is (Acceleration due to gravity $= 10 \ m \ s^{-2}$)

$A$ particle is released from a height $h$. The particle is given a constant horizontal velocity. Assuming $g$ remains constant everywhere, which graph correctly represents the kinetic energy $E$ of the particle with respect to time $t$?