Question

4 A circus trapeze consists of a bar suspended by two parallel ropes, each of length , allowing performers to swing in a vertical circular arc (Figure P8.12). Suppose a performer with mass m holds the bar and steps off an elevated platform, starting from rest with the ropes at an angle with respect to the vertical. Suppose the size of the performer's body is small compared to the length l , that she does not pump the trapeze to swing higher, and that air resistance is negligible. (a) Show that when the ropes make an angle 0 with the vertical, the performer must exert a force mg(3cos 0 2cos 0 ) in order to hang on. (b) Determine the angle 0; for which the force needed to hang on at the bottom of the swing is twice the performer's weight. USE THE OPPOSITE PAGE TO PRESENT SOLUTION TO PROBLEM 4

Answer 1

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