A firm is considering investing in a new piece of material handling equipment that should save on the current annual labor cost of moving the materials by hand. The device costs $750 can be expected to result in $500 annual savings for years 1, 2, and 3; then, it will have worn out and have to be replaced. Assume the interest rate that determines time value of money for this firm is 7% Required:
a. What is the payback period for the expenditure of the $1000?
b. Calculate the present worth (PW) of the three years of savings, assuming the savings occur at the end of each year of ownership.
c. Calculate the net present worth (NPW) of the investment.
d. Based on your answers to į and iii, should the firm invest in the equipment?

Amass of 1.5 kg of air at 120 kpa and 24°c is contained in a gas-tight, frictionless piston-cylinder device. the air is now compressed to a final pressure of 720 kpa. during the process, heat is transferred from the air such that the temperature inside the cylinder remains constant. calculate the boundary work input during this process.

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.

Fluids at rest possess no flow energy. a)- true b)- false