A block of mass is kept on an inclined plane of a lift moving down with acceleration of `2 ms^(-2)` What should be the minimum coefficient of friction to let the block move down with constant velocity?

Options

A. `mu = (1)/(sqrt(3)`
B. `mu = 0.4`
C. `mu = 0.8`
D. `mu =` not defined

Answer

a

Explanation

If block is sliding with constant velocity

`mg sin theta = mu N + ma sin theta`
`and N + ma cos theta = mg cos theta`
From (i) , `N = m(g - a) cos theta`
`mg sin theta = mu m(g - a)`
`cos theta + ma sin theta`
`10 xx (1)/(2)= mu (10 - 2)(sqrt(3))/(2) + 2 xx (1)/(2) rArr mu = (1)/(sqrt(3)`