$N$ number of balls of mass $m \mathrm{~kg}$ moving along positive direction of $X$ - axis, strike a wall per second and return elastically. The velocity of each ball is $u \mathrm{~m} / \mathrm{s}$. The force exerted on the wall by the balls in newton, is
A batsman hits a ball of mass 0.2 kg straight towards the bowler without changing its initial speed of $$6 \mathrm{~m} / \mathrm{s}$$. What is the impulse imparted to the ball?
A bullet of mass $$m$$ moving with velocity $$v$$ is fired into a wooden block of mass $$M$$, If the bullet remains embedded in the block, the final velocity of the system is
A block of mass ' $m$ ' moving on a frictionless surface at speed ' $v$ ' collides elastically with a block of same mass, initially at rest. Now the first block moves at an angle ' $\theta$ ' with its initial direction and has speed ' $v_1$ '. The speed of the second block after collision is