Question

A stone tied at 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 14s, what is the magnitude of acceleration of the stone?

• A. $30m{s}^{-2}$
• B. $31.6m{s}^{-2}$
• C. $35m{s}^{-2}$
• D. $34m{s}^{-2}$

Answer 1

The correct option is B $31.6m{s}^{-2}$

Frequency, $f=\frac{14}{14}=1Hz$

Angular velocity, $\omega =2\pi f=2\pi rad/s$

Acceleration of stone, $a={\omega }^{2}r=4{\pi }^2\times 0.8=31.6m/s^2$
Hence, the correct option is $\left(B\right)$