Week 1- Quiz 2 Flashcards
(21 cards)
What are the three principle stresses that exist?
Tension, compression, and shear
What is mechanics?
Mechanics deals with the analysis of forces acting on an object. The study of biomechanics applies the principles of mechanics to human and animal bodies.
What is tension stress?
Tension occurs when the external forces (load) applied are colinear and act in opposite directions (away from each other)
What are some examples of tension stresses that occur?
Tension stress occurs within the lateral ligaments as the foot is excessively inverted, within the patellar tendon as the quadriceps muscles contract , within the anterior longitudinal ligament of the lumbar area during increased lumbar lordosis, and within the conoid and trapezoid ligaments as the arm is elevated.
What is a compression stress?
Compression is present when the external forces applied are colinear and act towards each other.
What Are the examples of compression stresses?
Compression stress occurs within the patella femoral Joint as the quadriceps muscles contract, within the Glenohumeral joint when the shoulder muscles contract, within a muscle or bone when struck directly, and within cartilage or bone when directly loaded. Ex. Contusions, fractures, herniations.
What is a shear stress?
Shear results when two parallel forces, opposite in direction and not colinear, cause one point on a surface of an object to slide past a point on an adjacent surface.
What are some examples of shear stresses?
Shear stress may exist in epiphyseal plates as the separate parts of the bones are loaded: between the sacrum, disks, and vertebrae as the psoas muscle contracts; and between the skin and underlying tissue as the skin is abraded
What are the characteristics of force?
Force is composed of four specific characteristics. The magnitude of force, often denoted by a capital letter, is the amount push or pull. this amount of force acts along a line of application that in turn acts as a specific point of application. force also must be defined by its direction, which is indicated by an arrowhead on the line of application.
What is magnitude?
The magnitude of force, often denoted by a capital letter, is the amount of push or pull.
What is gravity?
The weight of an object is the result of gravitational force. The formula for defining gravitional force is W = mg! where W is the weight of the object, m is the mass of the object , and g is the constant acceleration caused by gravitational pull.
What is inertia?
The concept of inertia maintains that a body remains at rest or in uniform motion until acted upon by an outside force.
Although not a true force, inertia acts like a force because?
It resists the change in motion (or lack of it) of an object.
What is buoyancy?
Buoyant force tends to resist gravity. In water the magnitude of this force equals the weight of the water that the object displaces.
What is force?
The science of mechanics is concerned with forces. A force is simply defined as a push pull. An equation often used to defined force is F = ma, where F is the force, m is the mass of the object, and a is the acceleration of the object. By this definition, force is a entity that tends to produce motion.
What is load?
An outside force or group of forces acting on an object.
What is pressure?
Pressure defines how force is distributed over a an area. And is measured in terms of force/ unit area (e.g., pounds per square inch or N/cm2)
What is strength?
The term strength is often used to mean the ability of muscle or produce or resist a force. The greater the force produced by a muscle, the greater the strength of the muscle. This concept may be related to the ability of a muscle to overcome a load.
What is power?
Power is the rate of doing work or dissipating energy. Two formulas doe this entity expressed in terms of translatory (linear) motion are P= FV, where P stands for power, F for force, d for linear displacement, t stands for time, and v for linear velocity.
What is the three point bending principles?
Bending strain with tension develops parallel to the length of the beam in its convex portion. Compression stress develops parallel to the length of the beam on the concave portion. Shear stress is also produced maximally in two directions within the bending beam.
What is cantilever bending?
Cantilever bending one end of the beam is fixed. And the free end is loaded. In this situation tension created in the upper convex portion of the beam, where: compression occurs in the lower concave part. Example is the femur and lower limb as a whole.
