Question

A block of mass $0.1kg$ is held against a wall by applying a horizontal force of $5N$ on the block. If the coefficient 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. $0.98N$
• C. $4.9N$
• D. $0.49N$

Answer 1

The correct option is B $0.98N$

Since the block is held against a wall, the frictional force will be equal to the weight of the block, hence

$f=mg=\left(0.1kg\right)\left(9.8m/s^2\right)$
$=0.98N$