h ऊँचाई से छोड़ा गया एक गुटका चित्र में दर

In order to complete a full circle, the normal force when the block is at the highest point of circular ramp should be greater than zero,

$\mathrm{SO}$

if value of point $B=v_{B}$ Then,

At point $B, m g+N=\frac{m v_{B}^{2}}{R}$

$\mathrm{AS} N>0$

$\Rightarrow v_{B}^{2}>m g R$

At point $-A$

$\frac{m v_{A}^{2}}{2}-\frac{m v_{B}^{2}}{2}=m g(2 R)[A s \Delta K E=-\Delta P E]$

$\frac{m v_{A}^{2}}{2}=2 m g R+\frac{m v_{B}^{2}}{2}$

As $v_{B}^{2}>m g R$

$\Rightarrow \frac{m v_{A}^{2}}{2}>2 m g R+\frac{m g R}{2} \Rightarrow \frac{m v_{A}^{2}}{2}>\frac{5 m g R}{2}$

Also, $\frac{m v_{A}^{2}}{2}-0=m g h$

$\mathrm{As}, m v_{A}^{2}>5 m g R \Rightarrow m g h>\frac{5 m g R}{2}$

$\Rightarrow h>5 r/ 2$