Asingle-threaded 25 mm diameter power screw has a pitch of 5 mm. the vertical load on the screw reaches 5 kn. the coefficients of friction are 0.08 for the collar and 0.10 for the threads. the collar frictional diameter is 50 mm. find the overall efficiency and the torque required to raise and lower the load.

Agas contained within a piston-cylinder assembly e end nation about same energy states, 1 and 2, where pi 10 bar, v undergoes two processes, a and b, between the sam 0.1 m3, ui-400 kj and p2 1 bar, v2 1.0 m2, u2 200 kj: process a: process from 1 to 2 during which the pressure- volume relation is pv constant process b: constant-volume process from state 1 to a pressure of 2 bar, followed by a linear pressure-volume process to +20 0 state 2 kinetic and potential energy effects can be ignored. for each of the processes a and b, (a) sketch the process on p-v coordinates, (b) evaluate the work, in kj, and (c) evaluate process the heat transfer, in kj