A block weighing w is held against a vertical wall be pressing horizontally with a force F. Then, F needed to hold the block is

Options

A. equal to w
B. equal to `(w)/(mu)` only
C. greater than `(w)/(mu)` only
D. greater than or equal to `(w)/(mu)`

Answer

B

Explanation

`F-N+0`
`implies " "F-N`
Further, `" "f=muN=w`
`implies mu F=w implies F=(w)/(mu)`