stone is tied to one end of a string $50\, cm$ long is whirled in a horizontal circle with a constant speed. If the stone makes $10$ revolutions in $20\, s$, what is the magnitude of acceleration of the stone ......... $cm/s^2$
$493$
$720$
$860$
$990$
stone is tied to one end of a string $50\, cm$ long is whirled in a horizontal circle with a constant speed. If the stone makes $10$ revolutions in $20\, s$, what is the magnitude of acceleration of the stone ......... $cm/s^2$
$a = 4{\pi ^2}{n^2}r = 4{\pi ^2}{\left( {\frac{1}{2}} \right)^2} \times 50 = 493\,cm/{s^2}$