Agas refrigeration cycle with a pressure ratio of 4 uses helium as the working fluid. the temperature of the helium is -3°c at the compressor inlet and 54'c at the turbine inlet. assume isentropic efficiencies of 88 percent for both the turbine and the compressor (given: the properties of helium are cp=5.1926 kj/kg k and k = 1.667.) determine the mass flow rate of the helium for a refrigeration rate of 30 kw. the mass flow rate of the hellum is kg/s? ?

An electrical motor raises a 50kg load at a construct velencity .calculate the power of the motor, if it takes 40sec to raise the load through a height of 24m(take g =9.8n/g)

Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.

Afour cylinder four-stroke in-line engine has a stroke of 160mm, connecting rod length of 150mm, a reciprocating mass of 3kg and its firing order is 1-3-4-2. the spacing between cylinders is 100mm. i. show that the engine is in balance with regard to the primary inertia forces and primary 3. a and secondary inertia couples. li determine the out of balance secondary inertia force ii. propose ways of balancing this out of balance force and discuss the challenges that will arise