Question

A string of length l fixed at one end carries a mass m at the other end. The string makes $\frac{2}{\pi }rev/s$ around the axis through the fixed end as shown in the figure, the tension in the string is

• A. 16 ml
• B. 4 ml
• C. 8 ml
• D. 2 ml

Answer 1

The correct option is A 16 ml

$Tsin\theta =mr{\omega }^2$
or $Tsin\theta =m\left(lsin\theta \right){\omega }^2$
$\therefore T=ml{\omega }^2=ml(2\pi f{)}^2$
$=ml{(2\pi \times \frac{2}{\pi })}^2=16ml$