F T R

F T R 1.5” 6” Forces generated on the foot while a 150 lb man is standing (on 2 legs)? Determine F What is tension generated in achilles tendon (connected to gastronemius muscle) during 2 legged stance? Determine T 150 FF

75 lbs T R 1.5” 6” What is tension generated in achilles tendon (connected to gastronemius muscle) during 2 legged stance? Determine T

2 legged stance –300 lbs of load through gastroc and tendon –Difference between tendons and ligaments? –Tendon will stretch-by how much? What do we need to calculate strain?

0.8 kg/mm2 would cause 3.5% elongation Can’t find a modulus and use Hooke’s law-why?

In fact, σ-ε curve is; –nonlinear –Age –Health –Rate of test –?? others Steel and Aluminum are ‘linear elastic’ What is force (F) and amount of stretch (ε) if we jump? Fast Slow

–flex our knees and push generating a rxn on our feet (F1)and momentum has to change –Momentum= –Newton said external forces can change momentum and called it an Impulse –Need to find velocity

Jump- raising our potential energy but..conservation of energy we must generate kinetic energy—, where g=32 ft/s 2 and he jumped 2 ft So, F1= So, 175 # due to impulse and 150 # due to weight, assuming 2 legged jump

F= Go back to FBD, Now what is stretch of tendon FF F T R 1.5” 6”

1.8 kg/mm2 would cause 6% elongation Tendons can fail around 10% strain