Question

A stone tied to the end of a string 80 cm long is whirled in a horizontal circle with a constant speed. If the stone makes 14 revolutions in 25 s, what is the magnitude and direction of acceleration of the stone ?

Answer 1

Frequency $f=\frac{14}{25}Hz$
Angular velocity $\omega =2\pi f=\frac{2\times 14\pi }{25}rad/s=3.52rad/s$

Acceleration is $a={\omega }^{2}r={3.52}^2\times 0.8=9.9m/s^2$
The direction is along the radius at every point towards the centre.