A bone fixation device is used following a femoral fracture consisting of a plate and two screws. If the radius of each screw is 4mm and the weight of the patient is 950N (assume all 950N are exerting a downward force on the device for simplicity), determine the shear stress exerted on the screws when the patient in balancing on one leg (the leg with the fixation plate). Enter your answer in MPa.
Added by Judith V.
Close
Step 1
The weight of the patient is 950N, and there are two screws supporting this weight. Therefore, each screw is supporting half of the total weight. Total force on each screw = 950N / 2 = 475N Show more…
Show all steps
Your feedback will help us improve your experience
Sri K and 66 other Physics 101 Mechanics educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
Problem 2 (9 pts): Consider a fixation device consisting of a plate and four screws, used to stabilize fractured bones. During a single leg stance, a person can apply the entire weight to the ground via a single foot, which has a compressive effect on the leg, its bones, and joints. In the case of a patient with a fractured leg bone (femur), this force F is transferred from below to above (distal to proximal) the fracture through the screws of the fixation device. The diameter of the screws is D = 5 mm and the weight of the patient is W = 700 N. The plate dimensions are 20 mm wide, 60 mm long, and 1 mm thick. A. Draw the free-body diagram of the screws. B. Determine the shear stress exerted on each screw of the four-screw fixation device during a single leg stance on the leg with a fractured bone. C. Determine the compressive stress of the plate at its center. Assume the distribution is constant through the center axis.
Sri K.
Adi S.
When a large bone such as the femur is broken, the two pieces are often pulled out of alignment by the complicated combination of tension and compression forces that arise from the muscles and tendons in the leg (see the X-ray image in Fig. P3.64A). To realign the bones and allow proper healing, these forces must be compensated for. A method called traction is often employed. If a total tension force of $400 \mathrm{N}$ is applied to the leg as depicted in Eigure $\mathrm{P} 3.64 \mathrm{B}$ to realign the parts of the femur, how much mass $m$ must be attached to the bottom pulley?
Forces and Motion in One Dimension
Cables, Strings, and Pulleys: Transmitting Forces from Here to There
Recommended Textbooks
University Physics with Modern Physics
Physics: Principles with Applications
Fundamentals of Physics
Transcript
18,000,000+
Students on Numerade
Trusted by students at 8,000+ universities
Watch the video solution with this free unlock.
EMAIL
PASSWORD