posted by Annette .
A 79-kg sprinter accelerates from rest to a speed of 11.0 m/s in 4.8 s.
(a) Calculate the mechanical work done by the sprinter during this time.
(b) Calculate the average power the sprinter must generate.
(c) If the sprinter converts food energy to mechanical energy with an efficiency of 25%, at what average rate is he burning Calories?
(d) What happens to the other 75% of the food energy being used?
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a. a = (V-Vo)/t = (11-0)/4.8=2.29 m/s^2.
d = 0.5a*t^2 = 0.5*2.29*(4.8)^2=26.4 m.
Work = F*d = mg*d = (79*9.8) * 26.4 =
b. P = F*d/t = 20439/4.8 = 4258 J/s =