$A$ rigid body of mass $4 \ kg$ initially at rest moves under the action of an applied horizontal force of $18 \ N$ on a table with a coefficient of kinetic friction of $0.2$. The work done by the applied force on the body in $10 \ s$ will be $.... \ J$.

$A$ boat of mass $1000 \,kg$ goes from rest to a speed of $20.0 \,m/s$ in $5.0 \,s$. The water exerts a constant drag force and the acceleration of the boat is constant. If the average power required by the boat is $45000 \,W$, then the magnitude of the drag force is: (in $\,N$)

If a lighter body (mass $M_1$ and velocity $V_1$) and a heavier body (mass $M_2$ and velocity $V_2$) have the same kinetic energy,then

The position $x$ of a particle moving along the $x$-axis at time $t$ is given by the equation $t = \sqrt{x} + 2$,where $x$ is in metres and $t$ is in seconds. The work done by the force in the first $4 \ s$ is .............. $J$.

$A$ simple pendulum of length $L = \frac{10}{3} \text{ m}$ with a bob of mass $M = 3m$ is hanging freely from a rigid support. $A$ bullet of mass $m$ is fired with a velocity $u = 50 \text{ ms}^{-1}$ from the ground at an angle $\theta$ with the horizontal. When the bullet is at its highest point of its trajectory,it collides head-on with the bob of the pendulum and gets embedded in the bob. After collision,if the pendulum moves through a maximum angle of $120^{\circ}$,then the value of $\theta$ is $(g = 10 \text{ ms}^{-2})$.

$A$ ball of mass $m = 60 \text{ g}$ is shot with speed $v_0 = 22 \text{ m/s}$ into the barrel of a spring gun of mass $M = 240 \text{ g}$ initially at rest on a frictionless surface. The ball sticks in the barrel at the point of maximum compression of the spring. What fraction of the initial kinetic energy of the ball is now stored in the spring?