Question

A block of mass $2\, kg$ rests on a horizontal surface. If a horizontal force of $5\, N$ is applied on the block the frictional force on it is $\left(\mu_{k}=0.4, \mu_{s}=0.5\right)$

• A. 5 N
• B. 10 N
• C. 8 N
• D. zero

Answer 1

Answer: (A)

Minimum force required to move the block
$=\mu_{s} m g=0.5 \times 2 \times 9.8=9.8 \,N$
Since the force applied is only $5 N$, the block fails to move.
$\therefore $ Frictional force $=$ applied force $=5\, N$