To practice Problem-Solving Strategy 8.1 Static equilibrium problems. When you l

Question

To practice Problem-Solving Strategy 8.1 Static equilibrium problems. When you lift an object by moving only your forearm, the main lifting muscle in your arm is the biceps. Suppose the mass of a forearm is 1.50 kg. If the biceps is connected to the forearm a distance dbioeps 2.50 cm from the elbow, how much force Fbiceps must the biceps exert to hold a 950 g ball at the end of the forearm at distance dball J 36.0 cm from the elbow, with the forearm parallel to the floor? How much force F lbow must the elbow exert (Figure 1) Figure 1 Y of 1 Biceps ball biceps forearm gabalu ball gdball, T biceps biceps you can solve for biceps. and Felbow Fi Part I What is the magnitude of the force exerted by the biceps Fbiceps? What is the magnitude of the force exerted by the elbow Felbow? Express your answers in newtons separated by a comma Ewa N, N Fiiceps, Felbow 119.952.95.942 Submit My Answers Give Up Incorrect Try Again, 3 attempts remaining ASSESS Evaluate whether the answer you obtained for the force exerted by the biceps is reasonable. Part J

Explanation / Answer

i) Sum the moments about the elbow:
0.95kg * 9.8m/s * 36cm + 1.5kg * 9.8m/s * 36cm/2 = Fbiceps * 2.5 cm
Fbiceps = 239.9 N

ii) Sum the vertical forces:
(0.95 + 1.2)kg * 9.8m/s + Felbow = Fbiceps
21.07N + Felbow = 239.9 N
Felbow = 218.83N

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