Question

A block of mass $10kg$ is moving on a rough surface as shown in the figure. The frictional force acting on the block is

• A. $20N$
• B. $60N$
• C. $40N$
• D. $80N$

Answer 1

The correct option is A $20N$

If body is moving on rough surface

Frictional force = ${\left(f_s\right)}_{max}=f_k=\mu mg=0.6\times 10\times 10=60N$

Since friction is self adjusting force maximum forc eof 60N is acting, but here only External force = 20N is acting so friction can acts is 20N

If external force increases then f will increase and go upto 60N beyond which object will move