Question

A force of $12$ $N$ acts on a body of mass $4$ $kg$ resting on a rough surface (coefficient of friction is $0.2$ and $g=10m{s}^{-2}$) The acceleration of the body in $m{s}^{-2}$ is

• A. 1
• B. 0.5
• C. 0.25
• D. zero

Answer 1

The correct option is A 1

For a block in equilibrium,
Equating forces along $Y-$axis,
Normal reaction, $N=mg$
Equating forces along $X-$axis,
$ma=F-f$
where $f=\mu mg$
$ma=F-\mu mg$
$a=\frac{F-\mu mg}{m}$
$a=\frac{12-0.2\times 4\times 10}{4}$
$a=\frac{12-8}{4}$
$a=\frac{4}{4}$
$a=1m{s}^{-2}$