In the figure shown, angle of repose is `45^(@)`.Find force of friction, net force and acceleration of the block when

(a) `theta = 30^(@)` (b)`theta = 45^(@)` (c)`theta = 60^(@)`

Explanation

If `theta le ` angle of repose , the block is stationary ,
`a = 0, F_("net") = 0` and `f = mg sin theta`,if `theta gt` angle of repose , the block will move ,
`f = mu mg cos theta`
`a = (m g sin theta - mu m g cos theta)/(m)`
`g sin theta - mu g cos theta` and `F_("net") = ma`
further `mu = tan alpha` `(alpha = "angle of repose" = 45^(@)`
`= tan 45^(@) = 1`