Question

A body of mass $100g$ is tied to one end of a $2m$ long string. The other end of the string is at the centre of the horizontal circle. The maximum revolution in one minute is $200$. The maximum tensible strength of the string is approx

• A. $8.76N$
• B. $8.9N$
• C. $87dyne$
• D. $87.64N$

Answer 1

The correct option is D $87.64N$

Given : $m=100g=0.1kg$ $R=2$ m

Frequency of revolution $f=200$ rpm $=\frac{200}{60}=3.33$ rps

Angular velocity $w=2\pi f=2\pi \left(3.33\right)=20.9$ rad/s

$\therefore$ Maximum tension in the string $T=mR{w}^2=0.1\times 2\times (20.9{)}^2\approx 87.64N$