Work and Energy Definition of Work Kinetic Energy Potential Energy Conservation of Mechanical Energy...
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Transcript of Work and Energy Definition of Work Kinetic Energy Potential Energy Conservation of Mechanical Energy...
![Page 1: Work and Energy Definition of Work Kinetic Energy Potential Energy Conservation of Mechanical Energy Power Efficiency.](https://reader037.fdocuments.net/reader037/viewer/2022102907/56649d8b5503460f94a717f8/html5/thumbnails/1.jpg)
Work and EnergyDefinition of Work
Kinetic EnergyPotential Energy
Conservation of Mechanical EnergyPower
Efficiency
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What is work?
The product of Force and distance moved
In the direction of the force
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In the direction of the force
Force and displacement must be in the same dimension
Parallel or antiparallelIf parallel, work done is positive
If antiparallel, work done is negativeIf force is perpendicular to
displacement, work done is zero.
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Negative work is also referred to asWork done against the antiparallel force
![Page 5: Work and Energy Definition of Work Kinetic Energy Potential Energy Conservation of Mechanical Energy Power Efficiency.](https://reader037.fdocuments.net/reader037/viewer/2022102907/56649d8b5503460f94a717f8/html5/thumbnails/5.jpg)
F
sPositive workWork = F x s
Units for Work: Nm or Joule, J
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Normal Force
Friction
Tension
Weight
• Work done by• Weight
• Zero• Normal
• Zero• Friction
•Negative
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Work = (F cos 30) x s
s
No work forGravity andNormal force
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Examples
![Page 9: Work and Energy Definition of Work Kinetic Energy Potential Energy Conservation of Mechanical Energy Power Efficiency.](https://reader037.fdocuments.net/reader037/viewer/2022102907/56649d8b5503460f94a717f8/html5/thumbnails/9.jpg)
How do you calculate for total work?
![Page 10: Work and Energy Definition of Work Kinetic Energy Potential Energy Conservation of Mechanical Energy Power Efficiency.](https://reader037.fdocuments.net/reader037/viewer/2022102907/56649d8b5503460f94a717f8/html5/thumbnails/10.jpg)
To calculate for total work
Sum of all of the work done by each forceOr
Net force x displacement
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Points on Total Work
If net force is zero, total work is also zero.If net work is not zero, then the body is
accelerating.Equation
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What is energy?
The stored ability to do work
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Kinetic Energy of an object
Stored ability to do work because of its motion.
Work –Energy Theorem
![Page 14: Work and Energy Definition of Work Kinetic Energy Potential Energy Conservation of Mechanical Energy Power Efficiency.](https://reader037.fdocuments.net/reader037/viewer/2022102907/56649d8b5503460f94a717f8/html5/thumbnails/14.jpg)
Examples
![Page 15: Work and Energy Definition of Work Kinetic Energy Potential Energy Conservation of Mechanical Energy Power Efficiency.](https://reader037.fdocuments.net/reader037/viewer/2022102907/56649d8b5503460f94a717f8/html5/thumbnails/15.jpg)
The work done by gravity
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Second case
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(Gravitational) Potential Energy of an object
Stored ability to do work as a result of it position.
Conservation of Mechanical Energy
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Examples
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Power
The rate of doing workWork done per unit time
EquationUnits
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Power and Quality of work are not the same.
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Efficiency
Power output per power input
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ExampleA simple pendulum, consisting of a mass m, is attached to the end of a 1.5 m length of string. If the mass is held out horizontally, which makes a 60°angle with the vertical, and then released from rest, what is its speed at the bottom?
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Example
If the 1000- kg roller coaster leaves Point Q from rest, how fast is it traveling at Point R?
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Example
If the 1000-kg roller coaster leaves Point Q from rest, what is its speed at Point S?
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Past Paper Example
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Past Paper Example
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Past Paper Example