A wooden box lying at rest on an inclined surface of a wet wood is held at static equilibrium by a constant force F applied perpendicular to the angle of inclination is `30 ^(@)` and the box and the inclined plane is 0.2 , the minimum magnitude of F is
( Use ` g= 10 m//s^2`)

Options

A. 0 N, as `30^@` is less than angle of repose
B. `ge 1N`
C. `ge 3.3N`
D. `ge 16.3N`

Answer

D

Explanation

Answer(4) `F_min = mg/mu (sintheta - mu costheta)`
` = (1xx 10)/0.2 (sin (30^2) - 0.2 (cos (30^@))`
= 10/0.2 `(1/2 - 0.2 (sqrt3/2))` .
= 50 (0.5 - 0.1732) .
therefore `F_min` = 16.34N .
Hence, minimum magnitude must be `ge` 16.3N