Question

The friction coefficients for healthy human synovial joints is commonly reported to be approximately:

Assuming a 2 meter tall body with mass 50kg is compressing a knee joint, how much additional work is required to stand, assuming constant normal force of a uniformly distributed mass and a one-quarter rotation of a 2 cm radius knee joint.

Express friction loss as percentage above the baseline total.

Do not forget to use center of mass and that humans commonly have two legs.

Answer 1