Answer is (4)
Coefficient of sliding friction has no dimension.
$\mathrm{f}=\mu_{\mathrm{s}} \mathrm{N}$
$\Rightarrow \mu_{\mathrm{s}}=\frac{\mathbf{f}}{\mathbf{N}}$
Answer is (4)
Coefficient of sliding friction has no dimension.
$\mathrm{f}=\mu_{\mathrm{s}} \mathrm{N}$
$\Rightarrow \mu_{\mathrm{s}}=\frac{\mathbf{f}}{\mathbf{N}}$