A66-kg base runner begins his slide into second base when he is moving at a speed of 3.4 m/s. the coefficient of friction between his clothes and earth is 0.70. he slides so that his speed is zero just as he reaches the base(a) how much mechanical energy is lost due to friction acting on the runner. (b) how far does he slide?

Athin electrical heater is inserted between a long circular rod and a concentric tube with inner and outer radii of 20 and 40 mm. the rod (a) has a thermal conductivity of ka = 0.15 w/(m*k), while the tube (b) has a thermal conductivity of kb = 0.8 w/(m*k) and its outer surface is subjected to convection with a fluid of temperature t= -15°c and heat transfer coefficient 60 w/(m2 *k). the thermal contact resistance between the cylinder surfaces and the heater is negligible. (a) determine the electrical power per unit length of the cylinders (w/m) that is required to maintain the outer surface of cylinder b at 15°c. (b) what is the temperature at the center of cylinder a?