A jack similar to the ones shown in Figure 10.5 uses a single square-thread screw to raise a load of 50 kN. The screw has a major diameter of 36 mm and a pitch of 6 mm. The thrust collar mean diameter is 80 mm. Running friction coefficients are estimated to be 0.15 for the screw and 0.12 for the collar:
(a) Determine the thread depth and helix angle.
(b) Estimate the starting torque for raising and lowering the load.
(c) Estimate the efficiency of the jack for raising the load.
(d) Estimate the power required to drive the screw at a constant one revolution per second.