Chapter 11, Problem 11.69P

BIO CALC Refer to the discussion of holding a dumbbell in Example 11.4 (Section 11.3). The maximum weight that can be held in this way is limited by the maximum allowable tendon tension T (determined by the strength of the tendons) and by the distance D from the elbow to where the tendon attaches to the forearm, (a) Let T_max represent the maximum value of the tendon tension. Use the results of Example 11.4 to express w_max (the maximum weight that can be held) in terms of T_max, L, D, and h. Your expression should not include the angle θ. (b) The tendons of different primates are attached to the forearm at different values of D. Calculate the derivative of w_max with respect to D, and determine whether the derivative is positive or negative, (c) A chimpanzee tendon is attached to the forearm at a point farther from the elbow than for humans. Use this to explain why chimpanzees have stronger arms than humans. (The disadvantage is that chimpanzees have less flexible arms than do humans.)