Engineering Answers

A dump truck hoists a box to an angle of 25° from the horizontal and pulls ahead 10 ft. Calculate the displacement of point A

 A mass of 0.9 kg of fluid, initially at a pressure of 15 bar and a temperature of 250oC, expands reversibly and polytropically to 1.5 bar. Find the final temperature, work and heat transfers and the change of entropy, if the index of expansion (n) is 1.25.

8. A 75% efficient cooling tower has a water entering at 45o C and wet bulb temperature of air entering at

25 oC. Find the water exit temperature of water.

A. 32oC B. 30oC C. 34.34oC D. 23.44oC

7. A 6 x 5 x 4 m room has a pressure of 101 kpa and temperature of 30oC (Psat = 5 kpa). If percent

relative humidity is 65%, find the mass of vapor (RV = 0.423 KJ/kgoK).

6. Air in a conditioned space has 26 oC db and 70% RH, find the wet bulb depression.

How many sheets of a dielectric are necessary to make a condenser having a capacity of 5.5nF when the sheets are 15cm x 30cm in area and 0.29cm thick? Use k = 8

To a closed system 150 kJ of work is supplied. If the initial volume is 0.6 m3 and pressure of the system changes as p = 8 – 4V, where p is in bar and V is in m3, determine the final volume and pressure of the system.