Question

If the collision is elastic find verticle component of velocity of block at B. just after collision.

• A. $\sqrt{45}$
• B. $\sqrt{15}$
• C. $-\sqrt{15}$
• D. 20

Answer 1

The correct option is A $\sqrt{45}$

According to the question,

To along the plane velocity just before collision

$v=\sqrt{2g\left(3\right)}$

$=\sqrt{60}m/s$

To along the plane velocity just after collision

$v_B=v\cos {30}^{\circ }$

$=\sqrt{45}m/s$