For each of the stated conditions, determine the probable production expressed in cubic yards per hour bank measure for a shovel equipped with a 3-cy bucket. The shovel has a maximum digging height of 30 ft. Use a 45-min-hour efficiency factor. question 9.3 on Construction planning and equipment methods

To save energy, the air supply to a 2000 ft office has been shut off overnight and the room temperature has dropped to 40°f. in the morning, the thermostat is reset to 70°f and warm air at 120 f begins to flov in at 200ft'/min. the air is well mixed within the room, and an equal mass flow of air at room temperature (changing with time) is withdrawn through a return duct. the air pressure is nearly 1 atm everywhere. ignoring heat transfer with the surroundings and kinetic and potential energy effects, estimate how long it takes for the room temperature to reach 70°f. plot the room temperature as a function of time.