Heat flows through a certain wall at a rate of h, when the temperatures on either side of the wall are tc and th the dimensions of the wall are a and b. you want to add a layer of insulation to the wall to reduce the rate of heat flow by percentage p. the insulating material is to have thermal conductivity k and thickness w. (a) draw two pictures: one of the original wall, and one with the layer of insulation added label all relevant information (b) derive an expression for w in terms of ht tc th a b p and . (c) calculate a value for wif k 0.0800 w/m-k a 3.00 m b 5.00 m tc 20.0 °c th-32.0 °c h1 1500 w p-90.0%

Abatter hits the baseball a with an initial velocity of v0 = 110 ft/sec directly toward fielder b at an angle of 23° to the horizontal; the initial position of the ball is 2.2 ft above ground level. fielder b requires 0.44 sec to judge where the ball should be caught and begins moving to that position with constant speed. because of great experience, fielder b chooses his running speed so that he arrives at the “catch position” simultaneously with the baseball. the catch position is the field location at which the ball altitude is 8.4 ft. determine the velocity of the ball relative to the fielder at the instant the catch is made.

In physics the desire of an object to keep doing what it is doing is termed?

The passing of heat through a material while the material itself stays in place. a. radiation b. conduction c. convection