A person stands on a scale on the ball of one foot at an angle of 13.3o, and the scale reads 67.5 kg. The distance between the ball of the foot and the leg bone is 3.8 cm, and the distance between the Achilles tendon attachment at the heel of the foot and the leg bone is 1.4 cm.
a) How much force does the Achilles tendon apply to keep standing on the ball of the foot?
b) How much does the force from the Achilles tendon change if you increase the angle to 30o?
c) What are the normal force on each foot when standing on the scale with one foot? And with two feet?