8. The Achilles tendon, which connects the calf muscles to the heel, is the thickest and strongest tendon in the body. In extreme activities, such as sprinting, it can be subjected to forces. According to one set of experiments, the average area of the Achilles tendon is 80.0 mm², its average length is 30 cm, and its average Young's modulus is 1480 MPa. a) How much tensile stress is required to stretch this muscle by 10.0 % of its length? b) If we model the tendon as a spring, what is its force constant? c) How many times of an 80-kg sprinter weight can be exerted on his Achilles tendon to stretch it by 2.5 cm?

8. The Achilles tendon, which connects the calf muscles to the heel, is the thickest and strongest tendon in the body. In extreme activities, such as sprinting, it can be subjected to forces. According to one set of experiments, the average area of the Achilles tendon is 80.0 mm², its average length is 30 cm, and its average Young's modulus is 1480 MPa. a) How much tensile stress is required to stretch this muscle by 10.0 % of its length? b) If we model the tendon as a spring, what is its force constant? c) How many times of an 80-kg sprinter weight can be exerted on his Achilles tendon to stretch it by 2.5 cm?

College Physics

11th Edition

ISBN:9781305952300

Author:Raymond A. Serway, Chris Vuille

Publisher:Raymond A. Serway, Chris Vuille

Chapter1: Units, Trigonometry. And Vectors

Section: Chapter Questions

Problem 1CQ: Estimate the order of magnitude of the length, in meters, of each of the following; (a) a mouse, (b)...

See similar textbooks

Similar questions

A man with a mass of 72.1 kg stands on one foot. His femur has a cross-sectional area of 8.00 cm2 and an uncompressed length 49.6 cm. Young’s modulus for compression of the human femur is 9.40 × 109 N/m2. A.) How much shorter is the femur when the man stands on one foot? B.)What is the fractional length change of the femur when the person moves from standing on two feet to standing on one foot?
Many caterpillars construct cocoons from silk, one of the strongest naturally occurring materials known. Each thread is typically 2.0 µm in diameter, and the silk has a Young's modulus of 4.0 x 10° N/m2. Assuming that there is no appreciable space between the parallel strands, how many strands N would be needed to N = strands make a rope 8.6 m long that would stretch only 1.02 cm when supporting a pair of 85-kg mountain climbers? Again assuming that there is no appreciable space between the parallel strands, what would be the diameter d of the rope? d = cm
The leg bone (femur) breaks under a compressive force of about 7.90 × 104 N for a human and 11.3 × 104 N for a horse. The human femur has a compressive strength of 160 MPa, whereas the horse femur has a compressive strength of 140 MPa. What is the effective cross-sectional area of the femur in a horse? (Note: Since the center of the femur contains bone marrow, which has essentially no compressive strength, the effective cross-sectional area is about 80% of the total cross-sectional area.)
Humans can bite with a force of approximately 808 N. If a human tooth has the Young's modulus of bone, a cross-sectional area of 1.3 cm2, and is 1.5 cm long, determine the change in the tooth's length during an 8.08 ✕ 102 N bite. ______________________ m
A solid copper cube has an edge length of 81.9 cm. How much stress must be applied to the cube to reduce the edge length to 81 cm? The bulk modulus of copper is 1.4 x 1011 N/m2.
A man with a mass of 68.3 kg stands on one foot. His femur has a cross-sectional area of 8.00 cm2 and an uncompressed length 50.4 cm. Young’s modulus for compression of the human femur is 9.40 × 109 N/m2. What is the fractional length change of the femur when the person moves from standing on two feet to standing on one foot?
Humans can bite with a force of approximately 796 N. If a human tooth has the Young's modulus of bone, a cross-sectional area of 1.1 cm2, and is 1.9 cm long, determine the change in the tooth's length during an 7.96 ✕ 102 N bite. m
80. Between each pair of vertebrae in the spinal column is a cylindrical disc of cartilage. Typically, this disc has a radius of about 3.0 X 10-² m and a thickness of about 7.0 x 10-3 m. The shear modulus of cartilage is 1.2 × 10' N/m². Suppose that a shearing force of magnitude 11 N is applied parallel to the top surface of the disc while the bottom surface remains fixed in place. How far does the top surface move relative to the bottom surface?
A steel guitar string with a diameter of 0.300 mm and a length of 70.0 cm is stretched by 0.500 mm while being tuned. How much force is needed to stretch the string by this amount? Young's modulus for steel is 2.0 x 1011 N/m2. O 1.22 N 24.5 N O 10.1 N 2.45 N O 12.2 N
The ratio of the tensile (or compressive) strength to the density of a material is a measure of how strong the material is "pound for pound." What is the strength of tendon (tensile strength 79.0 MPa, density 1100 kg/m^3)? What is the strength of steel (tensil strength 0.570 GPa, density 7700 kg/m^3)? What is the strength of bone (compressive strength 159 MPa, density 1590 kg/m^3)? What is the strength of concrete (compressive strength 0.410 GPa, density 2700 kg/m^3)?
An amusement park ride consists of airplane-shaped cars attached to steel rods. Each rod has length 15m and cross-sectional area 8.00cm2. Take Young's modulus for steel to be Y=2.0×1011Pa. How much is the rod stretched (change in length of ΔL) when the ride is at rest? Assume that each car with two people seated in it has a total weight of 1900N. When the ride is operating, it has a maximum angular speed of ω=8.0rev/min. How much is the rod stretched then?
The muscle fibers in muscle A have a pinnation angle of 25 degrees, while the muscle fibers in muscle B have a pinnation angle of 20 degrees.Two pennate muscles have the same cross sectional area and produce the same tensile stress. Which muscle can produce a greater amount of force? Muscle B Muscle A Muscle A and B produce the same force