Question

A block of mass $2\text{kg}$ is put on a rough horizontal surface having coefficient of friction $0.5$. The acceleration of block and frictional force acting on block if $F=7\text{N}$ is (Take $g=10{\text{m/s}}^2$)

• A. $\frac{7}{2}{\text{m/s}}^2,10\text{N}$
• B. $0{\text{m/s}}^2,7\text{N}$
• C. $0{\text{m/s}}^2,10\text{N}$
• D. $5{\text{m/s}}^2,5\text{N}$

Answer 1

The correct option is B $0{\text{m/s}}^2,7\text{N}$

By the free body diagram,

Here the applied force is $7\text{N}$, for the limiting frictional force

$f_{max}=\mu N=0.5\times 20=10\text{N}$,

here the applied force $F<f_{max}$ and hence the block will not move and the friction is static in nature, $f=7\text{N}$

Hence, option B is the correct answer.