A block of mass `4kg` pressed againest a rought wall by two perpendicular horizontal forces `F_(1) and F_(2)`as shown in figure Coefficient of static friction between the block and wall is `0.6` and that of kinetic friction is `0.5`

For `F_(1) = 150 Nand F_(2) =100 N` find the direction and magnitude of friction acting on the block

Options

A. `90 N` making an angle of `tan^(-1)((2)/(5))` with the horizontal in the upward direction
B. `75 N` making an angle of `tan^(-1)((2)/(5))` with the horizontal in the upward direction
C. `107.7 N` making an angle of `tan^(-1)((2)/(5))` with the horizontal in the upward direction
D. Zero

Answer

b

Explanation

For `F_(1) = 150 N,f_(L) = 0.6 xx 150 = 90 N`
As component of resulant force along the surface is `107.7N` end it is greater than `f_( L)` so kinetic friction comes into `f = mu_(k)N_(1) = 0.5 xx 150 = 75N ` its direction is opposite the component force along the surface