Question

regarding coefficients of friction of synovial joints, the kinetic coefficient of friction is ______ the static coefficient of friction.
a) equal to
b) slightly higher than
c) much higher
d) much lower than

Explanation:

Synovial joints have a specialized lubricated structure. Static friction resists the start of motion, while kinetic friction acts during motion. For these joints, the kinetic friction coefficient is far smaller than the static one due to the synovial fluid's lubricating effect that reduces friction once motion begins.

Answer:

d) much lower than