Question

A ball of mass $3kg$, moving with a speed of $10m{s}^{-2}$ strikes a wall at an angle of ${60}^o$ (as shown). The ball rebounds at the same speed. Find the impulse imparted to the ball by the wall.

Answer 1

Velocity along the mirror i.e., $10cos{60}^0$ will remain same only the perpendicular component i.e. $10cos{30}^0$ will get $reversed$ so net change in velocity will be $double$ of initial perpendicular component i.e $\Delta v=$ $20cos{30}^0=10\sqrt[2]{23}=17.32m/s$

Impulse is nothing but change in momentum i.e. $m\Delta v=3\times 17.32Kgm/s=51.96Newton-second$