Question

A block of mass $2$ $kg$ is lying on a floor. The coefficient of friction is $0.4$. If a force of $2.5$ $N$ is applied on the block as shown in the figure , then the magnitude of frictional force will be:

• A. $7.5$ $N$
• B. $10$ $N$
• C. $2.5$ $N$
• D. $5$ $N$

Answer 1

The correct option is C $2.5$ $N$

Given:
$\mu =0.4F=2.5$ $N$
$m=2$ $kg$
$N=mg=20$ $N$
The max value of friction $=\mu N=0.4\times 20=8$ $N$
Since, the force applied is $2.5$ $N$ there is no need for friction to attain its max. value.
$\therefore$ Frictional force $=2.5$ $N$