Question

A block of mass $10kg$ is placed on a rough horizontal surface whose coefficient of friction is $0.5$. If a horizontal force of magnitude $100N$ is applied on the block, then acceleration of the block will be $[\text{Take}g=10m{s}^{-2}]$

• A. $10m{s}^{-2}$
• B. $5m{s}^{-2}$
• C. $15m{s}^{-2}$
• D. $0.5m{s}^{-2}$

Answer 1

The correct option is B $5m{s}^{-2}$

The said condition can be depicted as shown below



Here it is given that
$m=10kg,g=10m{s}^{-2},\mu =0.5\text{and}F=100N$
$\therefore$ Force of friction, $f=\mu N=\mu mg$
$\Rightarrow f=0.5\times 10\times 10=50N$
Force that produces acceleration,
$F^{\prime }=F-f=100N-50N=50N$
Thus, acceleration of the block, $a=\frac{F^{\prime }}{m}=\frac{50}{10}=5m{s}^{-2}$