Effect of a Window in a Door. A carpenter builds a solid wood door with dimensions 2.00 m * 0.95 m * 5.0 cm. Its thermal conductivity is k = 0.120 W>m # K. The air films on the inner and outer surfaces of the door have the same combined thermal resistance as an additional 1.8-cm thickness of solid wood. The inside air temperature is 20.0C, and the outside air temperature is -8.0C. (a) What is the rate of heat flow through the door? (b) By what factor is the heat flow increased if a window 0.500 m on a side is inserted in the door? The glass is 0.450 cm thick, and the glass has a thermal conductivity of 0.80 W>m # K. The air films on the two sides of the glass have a total thermal resistance that is the same as an additional 12.0 cm of glass
Jordan Counsel Homework 5 1. How much camber should there be in a ski, with a running surface of 150cm, so that when half a 180lb skier’s weight is applied the pressure distribution over the length of the ski is constant Assume that the ski is resting on a flat, stiff surface, and that the ski has a constant section modulus (although we know this will not be good for flexing into a uniform arc)- rectangular cross-section of 20mm by 60mm and equivalent elastic modulus of 14,000MPa. Delta L = (F/(AY)) * L 0 -6 6 (180 (.959) (9.8)(1.5))/((20 * 60) x 10 )* (14000 x 10 ) -5 =7.15 x10 m
