3. A 75kg runner runs along flat ground at 4 m/s. Each 1.1 m long stride, the body centreof mass is lowered by 8.0 cm. Assume that muscles are 19%

efficient, and that the 34°Cskin has emissivity 0.9, exposed surface area 1.5 m² and that the surroundings are at25°C. ) find the work done per stride b) find the work done per second -) find the rate of thermal energy production in the muscles D find the rate of energy radiation from the skin e)using h= 5 W/m*K find the rate of convective loss from the skIH O find the rate of perspiration required to keep the body at a constant temperature