Make your own free website on Tripod.com
Geoff Wan's Physics 12 notes

These are the notes that Geoff painstakingly types out so that public can be enlightened with physics and maybe even get a better understanding of it. Got any questions? E-mail me!!



Physics 12



Table of Contents:



Ooops, I wanted to see the Chemistry notes. No prob. Click here to get there.


Significant Figures

Checklist for Graphs

1 Title
2 Name and label axis with appropriate quantities and units (do NOT use "x" and "y")
3 Include the origin
4 Use at least half the page
5 Choose axis and scale that creates a line at about 45 degrees
6 Do not join points. Draw a "best fit" line
7 Show slope interval and calculation
8 State an equation - include units for slope and intercept


Problem Solving

1. What is happening?
a) Read
b) Draw / Sketch
c) Graph
d) Identify your givens and unknowns

2. Equation
a) Select equation that relates known and unknown quantities....eg v = d/t
b) Solve algebraically for unknown.......eg t = d/v
c) Possibly search for second equation (2 step problems)

3. Substitute
a) Numbers and units
b) Estimate answer
c) Use dimensional analysis to check units

4. Evaluatuate
a) Use calculator
b) Check answer
c) Congratulate yourself <-------- VERY IMPORTANT!!!

Kinematics

Uniform Motion

Uniform Acceleration

Vectors

Methods of solving Vector problems

1.) Graphical analysis



2.) Analytical Method



Forces

Newton's Laws

1.) Inertia - an object moves at a constant velocity until an external force is acted upon it (external force can be a push, pull, or friction)

2.) F=ma - as you already know, Force = mass * acceleration

3.) Equal and Opposite Forces - and you probably already know that "for every action, there is an equal and opposite reaction" (but they MIGHT not be acting parallel to each other - that's why organisms can move...they exert a force diagonal to the ground, and the ground exerts an equal force upwards...that's how animals move...)

(but for stuff like a rock on the ground - the rock exerts a force straight down, and the ground exerts a force straight up - that's why stuff like rocks don't move unless there is some other force acting on it...confusing ain't it??)

Tension

Q: How the hell do you calculate tension???
A: first, you have to tell which of two situations apply:
1.) the object is moving up
2.) the object is moving down

Forces on Slopes

That's it!! That's all there is to forces on slopes!! Yay!

Work and Energy

(W)ork = (F)orce * (d)iplacement
(P)otential (E)nergy = (m)ass * g * (d)isplacement
(K)inetic (E)nergy = 1/2 * (m)ass * (v)elocity^2

Circular Motion



Uniform Circular Motion

a = v^2 / r OR a = 4(pi^2)R / T^2

  • where a is the centripetal acceleration,
  • v is the speed at which the object moves (?)
  • R is the radius of circular path at which the object orbits
  • and T is the time for one full period

    Newton's Universal Gravitation Law

  • Fg (Force of gravity on earth): = mg = GMm / R^2
    where m is the mass of the object,
    g is the acceleration due to gravity,
    G is the universal gravitational constant (6.7 * 10^-7 Nm^2/kg^2)
    R is the radius of the earth, or any other large piece of mass, like another planet, the sun, or even Rush Limbaugh. (radius of the earth = 6.4 * 10^6m)
    and M, which is the mass of the same big object (mass of the earth = 5.98 * 10^24 kg)

    Gravity



    Kepler's Laws

    Satellites and Weightlessness

    Electrostatics

    Static Electricity

    Coulomb's Law


    Electric Fields

    Electric Potential

    For a finite value of r:

    V =
    Ue
    ---
    q

    =>

    V =
    kQ
    ---
    r
  • work can be expressed in terms of voltage; W = Vq
  • Electric potential for 2 or more charges:
  • Vt is the arithmetic sum (as opposed to vectoral) sum of the individual potentials Between parallel plates:


    Electrical Energy

    Current

    Voltage

    Resistance

    Circuits

    Series Circuits

    Parallel Circuits


    Terminal Voltage & EMF

    EMF is...

    Terminal Voltage is...

    Meters

    Galvanometer

    Ammeter

    Voltmeters

    Voltmeter Sensitivity

    Power


    questions? comments? send them to gwan@yahoo.com