Introduction
Energy- Stuff that allows us to make changes
- Most important thing in the universe (kind of like the currency of the universe)
- Ability to do work
- Law of Conservation of Energy- Energy cannot be created or destroyed, it can only be transferred
- Energy in a closed system remains constant
- Energy is STORED, not used
Types of Energy
- Mechanical Energy = Potential Energy + Kinetic Energy
- Potential Energy= Based on position
- Gravitational Potential Energy (Ug or Eg)- Energy stored in the distance between the object and its source in the gravitational field
- Measured by distance between objects
- Mass and height affect it
- Kinetic Energy (Ke or Ek)- Energy stored in the motion of mass
- Measured by speed/velocity of the object
- Elastic Potential Energy (Us or Eel or Es)- Energy stored in the elastic force field
- Affected by the amount of stretch and the spring constant
- Internal Energy (Uint or Eint)- Energy stored in the random motion on the molecular level of an object's composition
- Measured by the temperature of an object (not heat)
- Temperature- Measured in kinetic energy
Energy Transfers Between Systems
- Working (W)- External push or pull on a system
- Heating (Q)- Temperature (average kinetic energy) difference causes energy to transfer from a warmer object to a cooler one
- Radiating (R)- Matter loses energy by radiating light and gains energy when it absorbs light
LOL Charts (hahaha)
Steps to Draw an LOL chart
- Decide what is in the system
- Draw the initial energy bar graph
- Determine there are any energy transfers into or out of the system
- Think about how the values of the different energy types change
- Draw the final energy bar graph
- Write the conservation of energy equation
Work
- Positive work- Energy transferred into the system Ef > Ei
- Negative work- Energy taken out of the system Ef < Ei
- We only care about the work done in the direction of the displacement
- W = F * ∆ x
- W = Force parallel to displacement * displacement
- 1 Joule = 1 (kgm^2)/s^2 = 1 Nm
- Area under a Force vs. displacement graph is the energy transferred through working
Work / Energy Calculations
Power
Power = Work / Time
1 Joule/second = 1 watt
1 horsepower = 746 watts
1 Joule/second = 1 watt
1 horsepower = 746 watts
4.1- Intro to Energy Mastering Physics Packet.pdf | |
File Size: | 4834 kb |
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4.2- Work/Energy Mastering Physics Packet.pdf | |
File Size: | 1466 kb |
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