week two overview wednesday (jan 29) –kinetic concepts (read ch 3 of hall) basic concepts related...
Post on 21-Dec-2015
215 views
TRANSCRIPT
![Page 1: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/1.jpg)
Week two overview • Wednesday (Jan 29)
– Kinetic concepts (Read Ch 3 of Hall) • Basic concepts related to kinetics• Mechanical loads on the human body• Tools for measuring kinetic quantities• Take text web-based practice exam
http://www.mhhe.com/hall4e
– Monday (February 3)• Vector resolution and summation (pp 76-80)• Center of mass – what it is and how to determine it in the
human body (pp 436-442)• Kinematics of projectile motion (pp 329-347)
![Page 2: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/2.jpg)
Objectives• Define and identify common units of measurement for mass, force,
weight, pressure, volume, density, specific weight, torque, and impulse• Identify and describe the different types of mechanical loads that act on
the human body• Identify and describe the uses of available instrumentation for
measuring kinetic quantities• Distinguish between vector and scalar quantities• Solve quantitative problem involving vector quantities using both
graphic and trigonometric procedures• Solve quantitative problem involving segmental calculation of total
body COM• Identify and describe kinematic characteristics of projectile motion
![Page 3: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/3.jpg)
Basic Concepts Related to Kinetics
• Inertia
• Mass
• Force– Free body diagram
• Center of Gravity
• Weight
• Pressure: Force/Area
• Volume: LWH
• Density: Mass/Vol
• Specific wt: Wt/Vol
• Torque: Fd
• Impulse: Ft
![Page 4: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/4.jpg)
Common Units for Kinetic Quantities
Quantity Symbol Metric Unit English UnitMass m kg slugForce F N lbPressure P Pa psiVolume (solids) V m3 ft3
(liquids) liter gallonDensity kg/m3 lb/ft3
Specific weight N/m3 lb/ft3
Torque T N-m ft-lbImpulse N • s lb • s
![Page 5: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/5.jpg)
All About Forces
• What is a force?
• Why study forces?
• Four properties of a force
• Mass, gravity, and weight
• Center of gravity Questions: – If you are standing in the anatomical position and you raise your ams
overhead, in what direction does you center of mass move?
– If you raise your arms to the front, why do you lean backward?
![Page 6: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/6.jpg)
Four Properties of forces:
Center of Mass of different objects:
![Page 7: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/7.jpg)
Free body diagrams:
![Page 8: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/8.jpg)
Sample Problem 1 on pressure
Is it better to be stepped on by a women wearing a spike or by a court shoe?
Known: wt = 556 N As = 4 cm2 Ac = 175 cm2
SolutionWanted: AnswerPressure exerted by the spike heel p = 139N/cm2
Pressure exerted by the court shoe p = 3.8 N/Cm2
Formulas: p = F/A 43.75 times more pressure
![Page 9: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/9.jpg)
Sample Problem on Pressure 2
• How much compressive stress is present on the L1, L2 vertebral disk of a 625 N woman, given that approximately 45% of body weight is supported by the disk
![Page 10: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/10.jpg)
Sample Problem on pressure 2
a) When she stands in anatomical positions?
Given: F = (625 N) (0.45) A = 20 cm2
Formula: Stress = F/A
Stress = (625 N) (0.45) / 20 cm2
Stress = 14 N / cm2
![Page 11: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/11.jpg)
Sample Problem on pressure 2
b) When she stands erect holding a 222 N suitcase?
Given: F = (625 N) (0.45) = 222 N A = 20 cm2
Formula: Stress = F/A
Stress = (625 N) (0.45) + 222 N / 20 cm2
Stress = 25.2 N / cm2
![Page 12: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/12.jpg)
Mechanical Loads on the Human Body
• Compression
• Tension
• Shear
• Torsion
![Page 13: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/13.jpg)
Bone loading modes: Compression – pushing together Tension – pulling apart Torsion – twisting Shear – cutting across
![Page 14: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/14.jpg)
Cutting across
![Page 15: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/15.jpg)
The Effects of Loading• DeformationWhen an external force is applied to the human body,
several factors influence whether an injury occursMagnitude and direction of force
– Area over which force is distributed– Load-deformation curve– Yield point (elastic limit)– Failure
![Page 16: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/16.jpg)
Load-deformation relationship:
Stress-strain curve:
![Page 17: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/17.jpg)
Repetitive vs. Acute Loads
• Repetitive loading
• Acute loading
• Macrotrauma
• Microtrauma
![Page 18: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/18.jpg)
Tools for Measuring Kinetic Quantities
• Electromyography (EMG)– To study neuromuscular function– Website: Surface electromyography systems, emg
electrode, emg acquisition analysis software
• Dynamography– Primarily employed in gait research– Starts, takeoffs, landings, baseball & golf swings, and
balance
![Page 19: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/19.jpg)
![Page 20: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/20.jpg)
![Page 21: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/21.jpg)
Force Platform – Measurement of ground reaction forces
![Page 22: Week two overview Wednesday (Jan 29) –Kinetic concepts (Read Ch 3 of Hall) Basic concepts related to kinetics Mechanical loads on the human body Tools](https://reader030.vdocuments.mx/reader030/viewer/2022032522/56649d6c5503460f94a4bfd3/html5/thumbnails/22.jpg)