
In the diagram shown, the normal reaction force between $2 \mathrm{~kg}$ and $1 \mathrm{~kg}$ is (Given…

- $25 \mathrm{~N}$
- $39 \mathrm{~N}$
- $6 \mathrm{~N}$
- $10 \mathrm{~N}$
Solution
$\begin{aligned}
f & =-\mathrm{F}_1+6 g \sin 30^{\circ}+\mathrm{F}_2 \\
f & =-60+6 g \sin 30^{\circ}+18 \\
f & =-60+6 \times 10 \times \frac{1}{2}+18 \\
f & =12 \mathrm{~N} \text { (downwards) } \\
\text {acceleration, } a & =\frac{f}{m}=\frac{12}{6}=2 \mathrm{~m} / \mathrm{s}^2
\end{aligned}$

As per question, the normal force between $2 \mathrm{~kg}$ and $1 \mathrm{~kg}$ is,
$\begin{aligned}
\mathrm{N}-18-10 \sin 30^{\circ} & =m a \\
\mathrm{~N}-18-10 \times \frac{1}{2} & =1 \times 2 \\
\mathrm{~N} & =2+23 \\
\mathrm{~N} & =25 \mathrm{~N}
\end{aligned}$
Asked in: NEET 2022 (Phase 2)