## Quick Reference

The angle λ such that tan λ=*μ*_{s}, where *μ*_{s} is the coefficient of static friction. Consider a block resting on a horizontal plane, as shown in the figure. In the limiting case when the block is about to move to the right on account of an applied force of magnitude *P*, *N*=*mg*, *P*=*F* and *F*=*μ*_{s}*N*. Then the contact force, whose components are *N* and *F*, makes an angle λ with the vertical.

*Subjects:*
Mathematics.