• A power screw moves a nut in a horizontal plane against a force of 75 kN. The screw has a single square thread of 6mm pitch on a major diameter of 40mm. The COF is 0.1. 1. Calculate Pr and Tr. 2. If Tr is > 50 N-m, select a suitable electric motor to rise the load with a speed of 5 mm/sec.