Question

Ball A of mass m after sliding from an inclined plane strikes elastically an another ball B of same mass at rest. Find the minimum height h so that the ball B just completes the circular portion of the surface at C. (All surfaces are smooth)

• A. h = $\frac{5}{2}$ R
• B. h = 2R
• C. h = $\frac{2}{5}$R
• D. h = 3R

Answer 1

Answer: (A)

h = $\frac{5}{2}$ R

Answer 2

$\sqrt{2gh}$= $\sqrt{5gR}$; 2h = 5R ; h = $\frac{5}{2}$R