A small block of mass of `0.1 kg` lies on a fixed inclined plane `PQ` which makes an angle `theta` with the horizontal. A horizontal force of `1N` acts on the block through its centre of mass as shown in the figure. The block remains stationary if ( take `g=10 m//s^(2))`

Options

A. `theta = 45^(@)`
B. `theta gt 45^(@)` and a frictional force acts on the block towards
C. `theta gt 45^(@)`and a frictional force acts on the block towards
D. `theta lt 45^(@)` and a frictional force acts on the block towards Q

Answer

A, C

Explanation

f = 0, If `mg sin theta = F cos theta implies theta = 45^(@)`
f towards Q, `mg sin theta gt F cos theta implies theta gt 45^(@)`
f towards P, `mg sin theta lt F cos theta implies theta le 45^(@)`