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 dbiceps = 2.50 cm from the elbow, how much force Fbiceps must the biceps exert to hold a 1000 g ball at the end of the forearm at distance dball = 35.0 cm from the elbow, with the forearm parallel to the floor? How much force Felbow must the elbow exert? (Figure 1)
Write an expression for ∑Fy. Take upward to be the positive y direction.
Express your answer in terms of some or all of the variables Fbiceps, Felbow, mforearm, mball, and g.