Question

A particle of mass $m$ strikes a wall with speed $v$ at an angle $30^{\circ}$ with the wall elastically as shown in the figure. The magnitude of impulse imparted to the ball by the wall is

• A. $mv$
• B. $\frac{m v}{2}$
• C. $2 mv$
• D. $\sqrt{3} mv$

Answer 1

Answer: (A)

Impulse = change in momentum
applying equation of change in momentum in horizontal direction
$I =m v \sin 30^{\circ}-\left(-m v \sin 30^{\circ}\right)$
$=2 m v\left(\frac{1}{2}\right)=m v$