PROBLEM $8\mathrm{.}122$ A cable is placed around three parallel pipes. Knowing that the coefficients of friction areand, determine $($a$)$ the smallest weightfor which equilibrium is maintained, $($b$)$ the largest weightthat can be raised if pipeis slowly rotated counterclockwise while pipesandremain fixed.

PROBLEM $8\mathrm{.}122$

A cable is placed around three parallel pipes. Knowing that the coefficients of friction are ${}_s=0\mathrm{.}25$ and ${}_k=0\mathrm{.}20,$ determine $($a$)$ the smallest weight $W$ for which equilibrium is maintained, $($b$)$ the largest weight $W$ that can be raised if pipe $B$ is slowly rotated counterclockwise while pipes A and $C$ remain fixed.