While running, a person dissipates about 0.60 J of mechanical energy per step per kilogram of body mass. If a 52 kg person develops a power of 64 W during a race, how fast is the person running? (Assume a running step is 1.5 m long.)
2006-10-12 08:33:07 · 5 answers · asked by activegirl 1 in Science & Mathematics ➔ Physics
Dimensional analysis:
0.6 J/(step*kg) | 1 step/1.5 m | 52 kg | 1s / 64J = 0.325 s/m
Take the reciprocal: v = 1 / 0.325 = 3.08 m/s
2006-10-12 09:10:32 · answer #1 · answered by Anonymous · 1⤊ 0⤋
1.5 meters per second
A Watt is a Joule per second. At .6 Joules per step it will take 106.67 steps to run the race. Since each step is 1.5 meters the race is 160 meters long, and it will take 106.67 seconds to run it.
2006-10-12 08:55:23 · answer #2 · answered by SteveA8 6 · 0⤊ 2⤋
W/step = 0.6*52 Nm/step = 0.6*52 watt*sec/step
V = 64W*step/(0.6*52 W*sec) = 64*1.5/(0.6*52) m/s
2006-10-12 08:54:03 · answer #3 · answered by Helmut 7 · 1⤊ 0⤋
there was a guy from chile who rans for 24 hours strait.. in the world book records without stopping
2016-03-28 06:43:03 · answer #4 · answered by Anonymous · 0⤊ 0⤋
21 mph
2006-10-12 08:35:03 · answer #5 · answered by dwh12345 5 · 0⤊ 1⤋