Question

A ball from a height h along the slope moves on the perfectly frictionless circular track of radius r as shown in the figure. If the ball just moves on the circular track without falling vertically downwards, the minimum height from where the ball should be released is –

• A. $\frac{3}{2}$r
• B. $\frac{5}{2}$r
• C. $\frac{7}{2}$ r
• D. r

Answer 1

Answer: (B)

$\frac{5}{2}$r

Answer 2

v ³ $\sqrt{5rg}$ or $\sqrt{2hg}$ ³ $\sqrt{5rg}$

\ h ³ $\frac{5}{2}$ r