Question

A block of mass $5kg$ is hold against a vertical wall with coefficient of friction $\mathrm{0.4.}$ then what will be the minimum horizontal force required so that the block does not slip $(g=10m/s^2)$:-

• A. $20N$
• B. $12.5N$
• C. $125N$
• D. $None$

Answer 1

The correct option is C $125N$

$Given$ :- Mass of block ( $m$ ) = 5 Kg

Coefficient of friction ( $\mu$ ) = 0.4

Acceleration due to gravity $\left(g\right)$ = 10 ${m/s}^2$

$ToFind$ :- Minimum horizontal force ( $F$ )

$Solution$ :- According to diagram , Block is balanced by equal and opposite forces

$\therefore$ $F=N$

$f=mg$

We know , $f_{max}$ = $\mu N$

$\therefore$ $mg=\mu F$

$F=\frac{mg}{u}$

$F=\frac{5\times 10\times 10}{4}$ $⟹$ $\underset{–}{125N}$

Hence , $\underset{–}{OptionC\left(125N\right)iscorrect.}$