Question

A body of mass $2kg$ lying on a smooth surface is attached to a string $3m$ long and then whirled round in a horizontal circle making $60$ revolution per minute. The centripetal acceleration will be

• A. $1.18m/s^2$
• B. $118.4m/s^2$
• C. $2.368m/s^2$
• D. $23.68m/s^2$

Answer 1

The correct option is B $118.4m/s^2$

Step 1: Find angular speed of the body.
Formula used: $\omega =2\pi n$
$n=60\frac{\text{rev}}{\text{min}}=\frac{60}{60}=1\text{rev}/s$
$\omega =2\pi n=2\pi \times 1=2\pi \text{rad}/s$

Step 2: Find centripetal acceleration
Formula used: $a_c={\omega }^{2}r$
$a_c=(2\pi {)}^2\times 3=118.4m/s$
Final Answer: (a)