- #1
Tina20
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Homework Statement
A forearm can be modeled as a 1.36 kg, 32.8 cm long "beam" (denoted by l) that pivots at the elbow which has a width of 2.26 cm (denoted by w) and is supported by the biceps. How much force must the biceps exert to hold a 540.0 g ball with the forearm parallel to the floor?
The diagram is similar to the one below except that the values on the diagram are not the values pertaining to this question. Use the values stated in the above question. The link below is just a reference as to what the diagram should look like
http://session.masteringphysics.com/problemAsset/1013607/12/jfk.Figure.P08.37.jpg
Homework Equations
Torque = I*alpha
where I is moment of inertia and alpha is angular acceleration
Net torque = 0
Fnet = 0 because the arm is in static equilibrium
The Attempt at a Solution
I don't know how to go about this.
Torque = Ia = 0
Torque = r*F
= 0.0226m *F
Tgravity = Mgx
where M = total mass
g = 9.8
x = distance of centre of mass to axis
Any ideas as to how to solve this? I need to complete it by tonight, so any help would be greatly appreciated!