Question

A block of mass 10 kg is released on rough incline plane. Block start descending with acceleration 2 m/$s^2$. Kinetic friction force acting on block is (take g = 10 m/$s^2$)

• A. 10 N
• B. 30 N
• C. 50 N
• D. $50\sqrt{3}$ N

Answer 1

The correct option is B 30 N

$a_{down}=2m/s{a}_{down}=gsin30-\mu gcos30f=\mu mgcos302=\frac{g}{2}-\frac{f}{m}\frac{f}{m}=5-2=3f=10\times 3=30N$