Question

A block weighs W is held against a vertical wall by applying a horizontal force F. The minimum value of F needed to hold the block is?

• A. Less than W
• B. Equal to W
• C. Greater than W
• D. Data is insufficient

Answer 1

The correct option is C

Greater than W

Here applied horizontal force (F) acts as normal reaction (R).
For holding the block,
Force of friction = Weight of block
$f=W\Rightarrow \mu R=W\Rightarrow \mu F=W\Rightarrow F=\frac{W}{\mu }$
As $\mu <1\therefore F>W$