Question

An insect trapped in a circular groove of radius $12\,cm$ moves along the groove steadily and completes $7$ revolutions in $100\,s$. The linear speed of the insect is

• A. $4.3\,cms^{-1}$
• B. $5.3\,cms^{-1}$
• C. $6.3\,cms^{-1}$
• D. $7.3\,cms^{-1}$

Answer 1

Answer: (B)

Here, $r = 12\, cm$, frequency, $\upsilon=\frac{7}{100}rps$
The angular speed of the insect is
$\omega=2\pi\upsilon=2\pi\times\frac{7}{100}=0.44\,rad\,s^{-1}$
The linear speed of the insect is $v= \omega r=0.44 \times 12$
$ = 5.3\, cm s^{-1}$