Physics 5A Discussion Worksheet 7 Problem 1. When a person stands on tiptoe, the total weight of the body is supported by the normal force iii exerted on the toe by the floor. A mechanical model for the situation is shown below. In the diagram, "l: is the tension force exerted on the foot by the Achilles tendon, l5 is the force exerted on the foot by the tibia, and the dashed lines are vertical. Assume that the normal force on the foot has magnitude N = 350 N. e=af FOOT" (a) Find the magnitude T of the Achilles tension. {b} Find the magnitude P of the tibial force. (Note: The angles in the diagram are rounded to two significant gures. Because of this, different methods for solving parts (a) and (b) may return different numerical values if you include more than two signicant digits. All answers should agree up to two digits.) (c) Model the Achilles tendon as an elastic medium with Young's modulus 1.5 GPa. If the tension you found in part (b) is applied to a tendon with unstretched length 15 cm and average cross-sectional area 0.45 cmz, by how much does the tendon stretch