A block of mass $2 \mathrm{~kg}$ is placed on an inclined rough surface $\mathrm{AC}$ (as shown in figure) of coefficient of friction $\mu$. If $g=10 \mathrm{~ms}^{-2}$, the net force (in $\mathrm{N}$ ) on the block will be

• A

  $10$
• B

  $20$
• C

  $10 \sqrt{3}$
• Correct answer
  D

  Zero

Solution

$\begin{aligned} \Rightarrow\left(F_{\text {net }}\right) \mathrm{H} & =m g \sin 30^{\circ}-\mu m g \cos 30^{\circ} \\ & =\frac{m g}{2}-\frac{1}{\sqrt{3}} m g \cdot \frac{\sqrt{3}}{2}\end{aligned}$ $F_{\text {net }}=0$

Hence, the correct answer is option: 'D'.