Question

A block of mass $m=2kg$ is passed against the vertical wall with a force $N=50N$. Friction coefficient between the wall and the block is $\mu =0.6$. Then:

• A. The friction force acting on the block in the position shown is $20N$
• B. The minimum force on has to exert vertically downward to make the block move is $10N$
• C. The minimum force one has to exet horizontaly and parallel to the wall to make the block move is $10\sqrt{5}N$
• D. All of the above

Answer 1

The correct option is A The friction force acting on the block in the position shown is $20N$

$mg=2\times 9.8\simeq 20N$ $\left(apporx\right)$

maximum friction force $,$ $f=\mu N$ that can act

$f=0.6\times 50$

$f_{max}=30N$

This is the maximum friction force that can act$.$

But since downward force is only $20N$ so to oppose it only friction force of magnitude $20N$ is required$.$

So$,$ the frictional force of magnitude $20N$ will act upon it $.$

Therefore$,$

Option $\left(A\right)$ is correct$.$