$\Rightarrow \mathrm{f}_{2}<\mu \mathrm{N}_{2}$

$\mathrm{f}_{1}+\mathrm{R}=\frac{\mathrm{mg}}{2}$            $\mathrm{N}_{1}=\frac{\mathrm{mg}}{2} \mathrm{cos} \alpha$

$\mathrm{f}_{2}=\mathrm{R}+\frac{\mathrm{mg}}{2} \quad \mathrm{N}_{2}=\frac{\mathrm{mg}}{2} \cos \alpha$

$\therefore \quad \mathrm{f}_{1}<\mathrm{f}_{2} \quad \therefore \quad \mathrm{N}_{1}=\mathrm{N}_{2}$

$\therefore \quad \sqrt{f_{1}^{2}+N_{1}^{2}}<\sqrt{f_{2}^{2}+N_{2}^{2}}$

contact force by brick in cludes friction $\&$ normal reaction both.