Postby Dante » Wed Feb 22, 2006 4:35 pm
hmm... I've always thought of it this way, an object has potential energy when it has the "potential" to gain energy (rock on a cliff, soda shook up in a bottle, two nicely sized masses of uranium) it doesn't neccesarily have to obtain this potential, it only has this potential. If moved or disturbed for instance you no longer have the potential (vaporize the rock, freeze the soda, dilute the uranium). However, kinetic energy is what happens when the object obtains some or all of its potential energy 1 second after, (the rock is kicked of the cliff, the soda bottle is opened over your friend,... KABOOM). Finally note that the term kinetic is associated with mass moving, a change in position with time. There are other types of descriptive terms associated with energy such heat (friction), electromagnetic (light) and gravitational (gravity waves) but these aren't normally discussed in high school math.
where do the #s go? force numbers go in F, mass numbers in m, accelerations in a, distances in x,y, z or d, speeds in v, times in t, temperatures in T, momentums in P, pressure also in P, torque in tau greek (looks like a subscript T with a ~ for the top), radius is r, diameter is also d, period is T, frequency is lowercase omega (w with round corners) when in radians, f when degrees, amplitude A, E is energy, E is electric field, c 3.0*10^8 is speed of light g 9.80665 m/s^2 is gravitational acceleration, G is gravitational constant, q is charge, k is a general constant for electric forces, fields, spring constants... you name it, but for electricity 1/(4*pi*epsilon_0) is also good, h_bar good for quantum mechanics, (if you are working with the schrodinger equation... God help you). h is the same times 2*pi, (good for energy per photon of light of a certain frequency... can't think of any more though at this time. Umm as for units I don't have time at the moment but if this is what you were looking for good luck,
Later,
Pascal