Aheating system must maintain the interior of a building at 20°c during a period when the outside air temperature is 5°c and the heat transfer from the building through its roof and walls is 3 × 106 kj. for this duty heat pumps are under consideration that would operate between the dwelling and
a. the ground at 15°c.
b. a pond at 10°c.
c. the outside air at 5°c.

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

The higher the astm grain-size number, the coarser the grain is. a)-true b)-false

Atmospheric air has a temperature (dry bulb) of 80° f and a wet bulb temperature of 60° f when the barometric pressure is 14.696 psia. determine the specific humidity, grains/lb dry air. a. 11.4 c. 55.8 d. 22.5 b. 44.1