PEDS100 Chapter Notes -Nuchal Ligament, Intervertebral Foramina, Articular Processes

54 views3 pages

tanbeaver257

25 Nov 2011

School

University of Alberta

Department

Physical Education and Sport

Course

PEDS100

Professor

Gail Amort- Larson

For unlimited access to Textbook Notes, a Class+ subscription is required.

Document Summary

Hyoid bone doesn"t articulate with any other bone in body. Cervical (7), thoracic (12), lumbar (5), sacral (1) 5 fused vertebrae, coccygeal (1) Between superior/inferior articular processes plane joints, little gliding occurs but small movements related to flexing,extending,rotation occur. Functions: encloses and protects spinal cord, supports the skull, supports weight the head, neck, and trunk, transfers weight to the lower limbs, helps maintain upright body position. Spinal curves: four curves; cervical curve, thoracic curve, lumbar curve, sacral curve. Thoracic and sacral curves called primary curvatures because they appear in fetal development, protect heart/lungs and reproductive organs. Lumbar and and cervical curves called secondary curvatures because they don"t appear for months after birth. Kyphosis: normal thoracic curve becomes exaggerated posteriorly (round back) common in ppl with osteoporosis. Lordosis: abdomen and buttocks protrude abnormally, caused by anterior exaggeration of lumbar curve. Bodies of neighboring vertebrae are connected by ligaments and separated by pads of fibrous cartilage called intervertebral discs.

Related Questions

A person bending forward to lift a load "with this back" rather than "with his knees" can be injured by large forces exerted on the muscles and vertebrae. The spine pivots mainly at the fifth lumbar vertebra, with the principal supporting force provided by the erector spinalis muscle in the back. Consider the model of a person bending forward to lift a 200-N object as shown in the figure. The spine and the upper body are represented as a uniform horizontal rod of weight 350 N, pivoted at the base of the spine. The erector spinalis muscle, attached at a point two-thirds of the way up the spine, maintains the position of the back. The angle between the spine and this muscle is 12.0^o. Find (a) the tension in the back muscle and (b) the compressional force in the spine.

olivebutterfly197

sangriaclam240

How fast can a racecar travel through a circular tum without skidding and hitting the wall? The answer could depend on several factors:

The weight of the car;
The friction between the tires and the road;
The radius of the circle;
The “steepness” of the turn.

In this project, we investigate this question for NASCAR racecars at the Bristol Motor Speedway in Tennessee. Before considering this track in particular, we use vector functions to develop the mathematics and physics necessary for answering questions such as this.

A car of mass m moves with constant angular speed to around a circular curve of radius R (Figure 3.20). The curve is banked at an angle . If the height of the car off the ground is h, then the position of the car at time t is given by the function

As the car moves around the curve, three forces act on it: gravity, the force exerted by the road (this force is perpendicular to the ground), and the friction force (Figure 3.21). Because describing the frictional force generated by the tires and the road is complex, we use a standard approximation for the frictional force. Assume that for some positive constant . The constant is called the coefficient of friction.

Let denote the maximum speed the car can attain through the curve without skidding. In other words, is the fastest speed at which the car can navigate the turn. When the car is navigate at this speed, the magnitude of the centripetal force is

The next three questions deal with developing a formula that relates the speed to the banking angle .

Now that we have a formula relating the maximum speed of the car and the banking angle, we are in a position to answer the questions like the one posed at the beginning of the project.

The Bristol Motor Speedway is a NASCAR short track in Bristol, Tennessee. The track has the approximate shape shown in Figure 3.22. Each end of the track is approximately semicircular, so when cars make turns they are traveling along an approximately circular curve. If a car takes the inside track and speeds along the bottom of turn 1, the car travels along a semicircle of radius approximately with a banking angle of . If the car decides to take the outside track and speeds along the top of turn 1, then the car travels along a semicircle with a banking angle of . (The track has variable angle banking.)

The coefficient of friction for a normal fire in Elly conditions is approximately . Therefore, we assume the coefficient for a NASCAR tire in dry conditions is approximately .

Before answering the following questions, note that it is easier to do computations in terms of feet and seconds, and then convert the answers to miles per hour as a final step.

11. Suppose the measured speed of a car going along the outside edge of the turn is . Estimate the coefficient of friction for the car’s tires.

goldpug777

PEDS100 Chapter Notes -Nuchal Ligament, Intervertebral Foramina, Articular Processes

Document Summary

Get access

Related textbook solutions

Physics: Principles with Applications

Related Documents

PEDS100 Chapter Notes -Articular Processes, Sacrum, Thoracic Vertebrae

CAPS 391 Lecture Notes - Lecture 3: Cervical Vertebrae, Axial Skeleton, Vertebra

BMSP 2135 Chapter Notes - Chapter 7.3: Coccyx, Cervical Vertebrae, Thoracic Vertebrae

Related Questions