A `70kg` man stands in contact against the inner wall of a hollow cylindrical drum of radius `3m` rotating about its verticle axis. The coefficient of friction between the wall and his clothing is `0.15` . What is the minimum rotational speed of the cylinder to enable the man to remain stuck to the wall (without falling) when the floor is suddenly removed?

Options

A. 4.7 rad/s
B. 9.8 rad/s
C. 24 rad/s
D. 1 rad/s

Answer

A

Explanation

`N = m R omega^(2)`
`mu N = mg`
From these two equations we get
`omega = sqrt((g)/(mu R))`
`= sqrt((9.8)/(0.15 xx 3)) = 4.7` rad/s