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 $25$ sec, what is the magnitude of acceleration of the stone.

• A. $680$ cm$/s^2$
• B. $720$ cm$/s^2$
• C. $860$ cm$/s^2$
• D. $990$ cm$/s^2$

Answer 1

The correct option is D $990$ cm$/s^2$

Given length of string = 80 cm and angular velocity $\omega$ = 2$\pi$f=$\frac{88}{25}$

And we know centripetal acceleration =$r{\omega }^2$

a=$80\times {\left(\frac{88}{25}\right)}^2$

=991.232 cm/s

=990 cm/s