R. Simmons is planning to build a log-cabin style beach house in Crescent Beach, Florida. She wants to make the strongest rectangular cross section 15 feet long ridge beam from this 18 inch diameter white oak log. a) Determine the base and height dimensions of the optimum cross section. (Hint: think section modulus, S) b) Using the cross section from a) and an allowable tensile stress of 1000 psi, what is the maximum allowable uniform distributed load intensity w that this beam would support with simple supports at the ends

Aquick transition of the operating speed of a shaft from its critical speed will whirl amplitude. (a) increase (b) limit (c) not affect (d) zero

What is the main objective of using reheat rankine cycle?

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 the air is well mixed within the room, and an equal mass flow of air at room temperature (changing with time) is withdrawn through a return duct.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.