Question

A stone tied to the end of a string of $80$ cm long, is whirled in a horizontal circle with a constant speed. If the stone makes $14$ revolutions in $25$ sec, then magnitude of acceleration of the same will be

• A. $990cm/{sec}^2$
• B. $680cm/{sec}^2$
• C. $750cm/{sec}^2$
• D. $650cm/{sec}^2$

Answer 1

Answer: (A)

$990cm/{sec}^2$

Centripetal $acceleration={\omega }^{2}r={\left(2\pi n\right)}^2\times r$

Where frequency, $n=\frac{14}{25}$

$\therefore acceleration=4\times \frac{22}{7}\times \frac{22}{7}\times \frac{14}{25}\times \frac{14}{25}\times 80$

$=990cm/{sec}^2$