Question

A Body cross the top most point of a vertical circle speed. What will be its acceleration when the string is horizontal?

• A. $3g$
• B. $6/g$
• C. $\sqrt{10}g$
• D. $2g$

Answer 1

The correct option is A $3g$

At the top most point, if body is moving with critical speed.

$T=0$

$\therefore mg=\frac{m{v}_t^2}{r}$

$\Rightarrow v_t=\sqrt{gr}$ $=$ velocity at top.

Total energy at top $=$ total energy when string is horizontal.

$v$

$\therefore$ acceleration, $a=\frac{v^2}{r}=\frac{3gr}{r}=3g$