Question

If the frequency of the rotating platform is f and the distance of a boy from the centre is r, which is the area swept out per second by line connecting the boy to the centre

• A. $\pi rf$
• B. $2\pi rf$
• C. $\pi r^{2}f$
• D. $2\pi r^{2}f$

Answer 1

Answer: (C)

$\pi r^{2}f$

Answer 2

Area swept by line in complete revolution $= \pi r^{2}$

If frequency of rotating platform is f per second, then Area swept will be $\pi r^{2}f$ per second.