Question

A stone tied to one end of string of $1m$ long is whirled in a horizontal circle with a constant speed. If the stone makes $10$ revolutions in $20s$, the magnitude of the acceleration of the stone is close to

• A. $98.6\frac{cm}{s^2}$
• B. $490\frac{cm}{s^2}$
• C. $987\frac{cm}{s^2}$
• D. $996\frac{cm}{s^2}$

Answer 1

The correct option is C $987\frac{cm}{s^2}$

Radius of circle, $r=1m=100cm$
Stone makes 10 revolutions per 20 sec
$\therefore$ revolutions per second $\left(f\right)$ is 0.5
Now angular velocity $\left(\omega \right)=2\pi f=\pi$ $rad/s$
centripetal accelaretion=${\omega }^{2}r={\pi }^2\times 100$ $cm/s^2$
centripetal acceleration = $987cm/s^2$