Aclassroom that normally contains 27 people is to be air conditioned with window air-conditioning units of 7.5-kw cooling capacity. a person at rest may be assumed to dissipate heat at a rate of about 375 kj/h. there are 14 lightbulbs in the room, each with a rating of 100 w. the rate of heat transfer to the classroom through the walls and the windows is estimated to be 14,500 kj/h. if the room air is to be maintained at a constant temperature of 21°c, determine the number of window air-conditioning units required.

If a particle moves along a path such that r : (3 sin t) m and ? : 2t rad, where t is in seconds. what is the particle's acceleration in m/s in 4 seconds? a)- 16.43 b)- 16.29 c)- 15.21 d)- 13.79

Asingle-geared blanking press has a stroke of 200 mm and a rated capacity of 320 kn. a cam driven ram is assumed to be capable of delivering the full press load at constant force during the last 15 percent of a constant-velocity stroke. the camshaft has an average speed of 90 rev/min and is geared to the flywheel shaft at a 6: 1 ratio. the total work done is to include an allowance of 16 percent for friction a) estimate the maximum energy fluctuation b) find the rim weight for an effective diameter of 1.2 m and a coefficient of speed fluctuation of 0.10

Aheavily insulated piston-cylinder device contains 0.02 m3 of steam at 300 kpa and 200 °c. 1.2 mpa. d this process. team is now compressed in a reversible manner to a pressure of etermine the entropy change and the work done on the steam during this process