A 3 kg ball strikes a heavy rigid wall with a speed of 10 m/s at an angle of 60◦. It gets reflected with the same speed and angle as shown here. If the ball is in contact with the wall for 0.20 s, what is the average force exerted on the ball by the wall?

A 3 kg ball strikes a heavy rigid wall with a speed of 10 m/s at an angle of 60◦. It gets reflected with the same speed and angle as shown here. If the ball is in contact with the wall for 0.20 s, what is the average force exerted on the ball by the wall? 

(a) 150 N

(b) 0 N

(c) 150 √3 N

(d) 300 N

[2000]

\[P_f - P_i = mv \sin 30^o - mv \sin 30^o \] \[textbf{x-axis:}\] \[P_f - P_i = -mv \cos 30^o - mv \cos 30^o \] \[= -2mv \cos 30^o \] \[= -2mv \cdot \frac{\sqrt{3}}{2} \] \[= -2(3)(10) \cdot \frac{\sqrt{3}}{2}\] \[ = -30\sqrt{3} \] \textbf{Average Force:} \[F = \frac{mv - mu}{t} \] \[= \frac{P_f - P_i}{t} \] \[= \frac{-30\sqrt{3}}{0.2} \] \[= -150\sqrt{3} \text{ N} \quad \text{(Force in x-axis)}\]