Problem 1.66

A small body \(A\) starts sliding down from the top of a wedge (Fig. 1.12\()\) whose base is equal to \(l=2.10 \mathrm{~m}\). The coefficient of friction between the body and the wedge surface is \(k=0.140 .\) At what value of the angle \(\alpha\) will the time of sliding be the least? What will it be equal to?