91Ó°ÊÓ

Power is to be transmitted between two shafts by a \(V\)-belt whose mass is \(0.9 \mathrm{~kg} /\) metre length. The angle of lap is \(170^{\circ}\) and the groove angle is \(45^{\circ}\). Assuming the coefficient of friction between the belt and the pulley to be \(0.17\), find \((a)\) velocity of the belt for maximum power and (b) power transmitted at this velocity. \([28.54 \mathrm{~m} / \mathrm{s}, 30.66 \mathrm{~kW}]\)

A screw jack has square threads of mean diameter \(6 \mathrm{~cm}\). of helix angle \(10^{\circ}\) and coefficient of friction 0.3. Determine the force that must be applied to the end of \(60 \mathrm{~cm}\) lever to \((a)\) raise (b) lower a weight of \(3000 \mathrm{~N}\). \([75 \mathrm{~N}, 18 \mathrm{~N}]\)