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Noctix
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Homework Statement
A person with upper arm vertical and forearm horizontal holds a 4.5-kg iron cannon ball. Assume the mass of the forearm and hand is 1.5 kg, with a center of mass 15 cm from the elbow. The center of the cannonball is 32 cm from the elbow, and the force of the biceps is applied 5.0 cm from the elbow. (a) What force is exerted on the forearm by the biceps muscle?
correct answer=330N
Homework Equations
Tau1+Tau2+...=0
The Attempt at a Solution
Tau(biceps)+Tau(forearm)+Tau(cannonball)=0
r1m1gsin90° + r2m2gsin90° + r3m3gsin90°=0
plug in variables=wrong answer
thanks in advance, i really appreciate all help.
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