A given object takes n times the time to slide down 45° rough inclined plane as it takes the time to slide down an identical perfectly smooth 45° inclined plane. The coefficient of kinetic friction between the object and the surface of inclined plane is :
1
\(1-\frac{1}{\mathrm{n}^2}\)
2
1 – n2
3
\(\sqrt{1-\frac{1}{\mathrm{n}^2}}\)
4
\(\sqrt{1-\mathrm{n}^2}\)