Chapter 11, Problem 89GP

BIO Peak Pedaling Torque The downward force produced by the quadriceps muscles during the power stroke of bicycle-pedaling motion is shown in Figure 11-67 as a function of the crank angle ϕ (see Figure 11-39.The force from these muscles decreases linearly, but the torque depends on the crank angle according to τ = rFsin (180° − ϕ). Use the information in the graph, together with a computer spreadsheet to find the angle ϕ at which the pedaling torque produced by the quadriceps muscle is a maximum. (Note that the actual torque applied to the crank is a result of the action of many muscles in addition to the quadriceps).

Figure 11-67 Problem 89