Final answer:
The static maximum frictional force in a knee supporting 66.0 kg of mass is roughly equal to the gravitational force on that mass, given as 646.8 N. Since the question presents multiple choice answers, and 646.8 N isn't an option, the closest provided value, 650 N, is the likely answer.
Step-by-step explanation:
The question asks about the maximum frictional force in the knee joint when supporting a certain mass. Specifically, it asks what this force would be for a person who is supporting 66.0 kg of their mass on one knee. To solve for the frictional force in a static scenario, where there is no movement of the joint, one would instinctively think to use the force of gravity acting on the mass (weight) and a coefficient of friction. However, this is a tricky question because typical physics problems involving friction between surfaces, where you'd use the equation µN (coefficient of friction multiplied by the normal force), do not directly apply to biological joints.
For a static joint like the knee supporting a stationary person, the maximum frictional force would theoretically be equal to the gravitational force acting on the supported mass if the friction between internal components of the knee was enough to resist any motion. Using the standard acceleration due to gravity (9.8 m/s2), the weight of the mass supported would be 66.0 kg * 9.8 m/s2 = 646.8 N.
Since typical friction in joints tends to be relatively low, and the values provided in the multiple choices do not include 646.8 N, the closest value to the calculated weight would be the likely answer, which is 650 N (Answer A). However, without knowing the actual coefficient of friction within the joint, which can vary greatly, a precise value cannot be easily determined. During strenuous exercise, forces in the knee can be substantially higher; this rise in force is due to the dynamic activities and muscle contractions rather than a simple increase in static friction. The actual frictional forces during these dynamic conditions are complex and cannot be calculated without additional specific biomechanical data.