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Work
joule (J)
Zero distance, no work
Displacement perpendicular to applied force, no work
What is power?
The rate at which work is done. (Walking vs running upstairs).
Units: watt and horsepower
How to Make Power?
work/time
Motion
an object changes its position with respect to time.
Position
the location of an object at any given time.
Energy
the ability to do work
KE (Kinetic energy)
Energy associated with motion. Results from work or change in potential energy. (Speed squared)
PE (Potential energy)
Energy associated with position. Work and kinetic energy can change into potential energy.
Four Forces:
Strong Nuclear
Weak Nuclear
Electromagnetic force
Gravitational force
Strong Nuclear force
solar energy generation
Weak nuclear force
Carbon -14 converting to Nitrogen-14
electromagnetic force
chemical bonds
Gravitational force
landslide
Energy Flow
based on the first two laws of thermodynamics
Energy Transformation
the change of energy from one form to another.
Conservation of Energy
Energy is never created or destroyed.
Energy can be converted from one form to another, but the total energy remains constant.
Conservation of Energy equation
Δ KE + Δ PE = 0
Energy Sources
nuclear energy, fossil energy and renewable sources like wind, solar, geothermal and hydropower.
Petroleum
a complex mixture of hydrocarbons that occur on Earth in liquid, gaseous, or solid form
Coal
a sedimentary deposit composed predominantly of carbon that is readily combustible.
Hydroelectric
a form of energy that harnesses the power of water in motion—such as water flowing over a waterfall—to generate electricity.
Solar
any type of energy generated by the sun
Wind geothermal
a renewable energy source because heat is continuously produced inside the earth.
Nuclear
a form of energy released from the nucleus, the core of atoms, made up of protons and neutrons.
Hydrogen
an energy carrier that can be used to store, move, and deliver energy produced from other sources.
Biofuels
offer a solution to one of the challenges of solar, wind, and other alternative energy sources.
Mechanical energy
Kinetic plus potential energy
Electrical energy
Charges, currents, etc.
Chemical energy
Energy involved in chemical reactions
Radiant energy
Electromagnetic energy; Visible light = small part of full spectrum
Nuclear energy
Energy involving the nucleus and nuclear reactions
Simple Machines
Work in equals work out
Force multiplied by ratio of distance
Simple machine examples
Inclined plane
Wedge
Screw
Lever
Wheel and axle
Pulley
1st Law of Thermodynamics
Energy cannot be created or destroyed.
2nd Law of Thermodynamics
For a spontaneous process, the entropy of the universe increases.
3rd Law of Thermodynamics
A perfect crystal at zero Kelvin has zero entropy.
Entropy
Measure of disorder
Phase changes
Melting
Boiling
Evaporation
Condensation
Melting
The process of a solid becoming a liquid (fusion)
Boiling
Heat going into a substance changes it from a solid to a liquid or a liquid to a gas.
Evaporation
the process of changing from a liquid to a vapor
Condensation
a substance is changed from the gaseous to the liquid state of matter
Kinetic molecular theory
Gasses are composed of a large number of particles that behave like hard, spherical objects in a state of constant, random motion.
Phases of matter
solid, liquid, and gas
Solid
a state of matter that retains its shape and density when not confined.
Liquid
conforms to the shape of its container but retains a nearly constant volume independent of pressure
Gas
a substance that does not have a definite volume (also called a fixed volume) or a definite shape.
Fahrenheit
scale based on 32° for the freezing point of water and 212° for the boiling point of water, the interval between the two being divided into 180 equal parts.
Celcius
a temperature scale based on 0o for the freezing point of water and 100o for the boiling point of water.
Kelvin Heat
the SI unit of thermodynamic temperature
Units
used to measure a physical quantity, such as mass or length
Specific Heat
the quantity of heat required to raise the temperature of one gram of a substance by one Celsius degree.
Latent Heat
the heat or energy that is absorbed or released during a phase change of a substance.
Conduction
the transfer of thermal energy between two objects by direct contact
Conduction example
ie. a metal cooking pot sitting in an air-conditioned house feels cold when you touch it.
Convection
motion in a gas or liquid in which the warmer portions rise and the colder portions sink
Convection example
ie. Hot air rising above a fire.
Radiation
a process where heat waves are emitted that may be absorbed, reflected, or transmitted through a colder body.
Radiation example
ie. The heating of the Earth by the Sun
Note 
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