A double-threaded Acme stub screw of 2-in. major diameter is used in a jack having a plain thrust collar of 2.5-in. mean diameter. Coefficients of running friction are estimated as 0.10 for the collar and 0.11 for the screw. a. Determine the pitch, lead, thread depth, mean pitch diameter, and lead angle of the screw

b. Estimate the starting torque for raising and for lowering a 5000-lb load.

c. What is the efficiency of the jack when raising the load?

d. Would the screw overhaul if a ball thrust bearing of negligible friction were used in place of the plain thrust washer?

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

Acompressor receives the shaft work to decrease the pressure of the fluid. a)- true b)- false

Afluid flows with a velocity field given by v=(x/t)i.. determine the local and convective accelerations when x=3 and t=1.