a) N/m^2
b) A = F/sigma
Muscles are attached to bones by means of tendons. The maximum force that a muscle can exert is
directly proportional to its cross-sectional area A at the widest point. We can express this relationship mathematically as F~max= σA, where σ (sigma) is a proportionality constant. σ is about the same
for the muscles of all animals and has a numerical value of 3.0 × 105kg m−1s−2.
(a) What are the units of σ in newtons and meters?
(b) In one set of experiments, the average maximum force that the gastrocnemius muscle in the back
of the lower leg could exert was measured to be 755 N for healthy males in their mid-twenties.
What does this result tell us was the average cross-sectional area, in cm2, of that muscle for the
people in the study?
1 answer