Question

Assume that the lower leg and the foot together have a combined mass of 4.0 kg , and that their combined center of gravity is at the center of the lower leg. As you hold your leg in this position, the upper leg exerts a force on the lower leg at the knee joint. What is the direction of this force?

Answer 1

Answer:

Downward

Explanation:

When the upper leg exerts a force on the lower leg and the combined center of gravity of both the legs lies at the center of the lower leg then the line of action of this force will be acting downwards.

• Like for any body which is placed on the other body is under the influence of gravity then the it will exert a force equal to its weight on the lower body in downward direction. Line of action of this force will be through the center of gravity of the upper body and the canter of gravity of both the bodies as a system will be the average their individual centers of the gravity.