Question

A block of mass $0.1kg$ is held against a wall applying horizontal force of $5N$ on the block. If coeff. of friction between the block and the wall is $0.5$, the magnitude of frictional force acting on the block is

• A. $2.5N$
• B. $0.49N$
• C. $0.98N$
• D. $4.9N$

Answer 1

The correct option is C $0.98N$

frictional force ($f$) is;

$f=mg$

if $\mu f>mg$

$\mu f=0.5\times 5=2.5$

$mg=0.1\times 9.8=0.98$

Hence limiting friction is $2.5$

Hence, frictional force acting on the block is;

$f=mg=0.1\times 9.8=0.98N$