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While running a person transforms about `0.60 J` chemical energy to mechanical energy per stop per kilogram of body mass. If a `60 kg` runner transform energy at a rate of `72 W` during a race, how fast is the person running? Assume that a running step is `1.5m` longA. `2.0 m//s`B. `3.0 m//s`C. `2.5 m//s`D. `sqrt((6 gh)/(13))` |
Answer» Correct Answer - D We first determine the energy output of the runner: `= (0.60 J//kg - step) (60 kg) ((1 step)/(1.50 m)) = 24.0 J//m` From this we calculate the force exerted by the runner per step: `F = (24 J//m) (1 N.m//J) = 24 N` |
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