Question

A tennis ball hits the floor with a speed $v$ at an angle $\theta$ with the normal to the floor. If the collision is inelastic and the co-efficient of restitution is $\varepsilon$, what will be the angle of reflection?

• A. $\tan ^{-1}\left(\frac{\tan \theta}{\varepsilon}\right)$
• B. $\sin ^{-1}\left(\frac{\sin \theta}{\varepsilon}\right)$
• C. $\theta \varepsilon$
• D. $\theta \frac{2 \varepsilon}{\varepsilon+1}$

Answer 1

Answer: (A)

$\tan \theta'=\frac{u \sin \theta}{e u \cos \theta}$
$\tan \theta'=\frac{1}{e} \tan \theta$
Since the floor is smooth. Hence tangential component of velocity remains unchanged