Question

A small ball of mass $m$ is released from rest from top of smooth track which has circular part at other end as shown in figure. The normal force exerted by track on the ball when it reaches to point $A,$ is

• A. $2mg$
• B. $\frac{mg}{2}$
• C. zero
• D. $mg$

Answer 1

The correct option is D $mg$

$v_1^2=2g(3R-2R)=\frac{m{v}^2}{r}$
$\therefore mg+N=\frac{m{v}_1^2}{R}$
$\Rightarrow N=mg$