A plank of mass 3m is placed on a rough inclined plane and a man of mass m, the coefficient of friction between the board and inclined plane is `mu = 0.5`, the minimum acceleration of man so that plank does not slide is :

Options

A. `8 m//s^(2)`
B. `4m//s^(2)`
C. `6m//s^(2)`
D. `3 m//s^(2)`

Answer

A

Explanation

`mgh = (1)/(2) mv^(2) + 2mgR`
`gh=(v^(2))/(2)+2gR`
Required velocity at the top, `v = sqrt(gR)`
`gh = (gR)/(2) + 2gR impliesh=(5)/(2)R`