A block of mass 2kg rests on a rough inclined plane making an angle of `30^@` with the horizontal. The coefficient of static friction between the block and the plane is 0.7. The frictional force on the block is

Options

A. `9.8 N`
B. `0.7 xx 9.8 xx sqrt(3) N`
C. `9.8 xx sqrt(3) N`
D. `0.7 xx 9.8 N`

Answer

A

Explanation

`f_(max) = mu N = mu mg cos theta`
`= 0.7 xx 2 xx 9.8 xx cos 30^(@)`
`= 0.7 xx 9.8 xx sqrt(3) N`
` = 11.7 N`
`mg sin theta lt f_(max)` , the block will not move
Friction `f = mg sin theta = 9.8 N`