Distance (fundamental): 3 dimensions; requires VECTORS
Motion (combines distance and time)
Forces cause changes in motion (Newtons Laws of Motion); types of force
Work and Energy (Conservation of Energy)
Power (rate a
One way to explain this action at a distance is this: each charge sets up
a field in space, and this field then acts on any other charges that go
through the space.
One supporting piece of evidence for this idea is: if you wiggle a charge,
the force on a
In order to account for both attractive and repulsive forces and describe
electricity fully, we needed to have two different kinds of charge, which we
call positive and negative.
Gravity with only attractive forces needed only one kind of mass.
When we break matter up, we find there are just a few fundamental
particles: electron, proton and neutron. (Well consider whether these
three are really fundamental or not in the last part of this course, and
whether there are any more fundamental particl
E from1 = k q1 / r122 for a point charge, and
g = G M / r2 for a mass. Why do both have an inverse square of
distance (1/r2) ?
If we consider that the field consists of a bunch of moving particles that
make up the field, the density of particles, and henc
In the first laboratory experiment, Simulation of Electric Fields, we use a
computer to perform the many vector additions required to look at the
electric field due to several charges in several geometries.
With the calculus, we can even determine the ele
Formula Cheat Sheet
F1on2 = k q1 q2 / r122
PE12 = k q1 q2 / r12
Fon 2 = q2 Eat 2
PEof 2 = q2 Vat 2
Eat 2 = k q1 / r122
Vat 2 = k q1 / r12
S F = ma
KEi + PEi = KEf +PEf +Elost
Ex = -DV / Dx
Through how many volts will a proton h
Since the potential energy of one charge due to another charge is:
PEel = k q1 q2 / r12
and since voltage is defined to be:
Vat 2 = PEof 2 / q2
we can find a nice formula for the voltage in space due to a single charge:
Vat 2 due to 1 = k q1 / r12Since vo
Suppose that we have an electron orbiting a proton such that the radius of
the electron in its circular orbit is 1 x 10-10m (this is one of the excited states
of hydrogen). How fast will the electron be going in its orbit?
qproton = +e = 1.6 x 10-19 Coul
The unit for voltage is, from the definition:
Vat 2 = PEof 2 / q2
volt = Joule / Coulomb .
Note that voltage, like field, exists in space,
while energy, like force, is associated with a particle!
In electricity we have:
PEof 2 = q2 * Vat 2 .
In gravity (a
When the interior of a massive star runs out of fuel, gravity will win and
cause the core to shrink. Since there is so much mass, there will be a
huge implosion of the core, which will cause a huge explosion of the
The power output in this supern
Since the ratio of neutrons/protons is bigger for U-238 than for the stable
isotopes of the two decay atoms (whichever two they happen to be), the
two decay atoms will have too many neutrons, and so will be
radioactive. This is the main source of the radi
Another element found in nature is 90Th232 .
This can be used in a breeder reactor, since
n1 + 90Th232
Th233 which decays (with a half life of 22.3 minutes and
27 days) to 92U233 which is a fissile material with a half life of 162,000
To run a
We can control sescape by controlling the size of the uranium fuel: we can
ideally have two sub-critical pieces of uranium and when we want, put the
two sub-critical pieces together to form a super-critical piece.
We can also control sabsorption by using
1. Find the potential energy of two or more point charges.
2. Find the net voltage at a point in space from one or more point charges.
3. Find the potential energy of a charge if you know the charge and the voltage at
the position of the charge.
Are the neutron, proton, electron, neutrino, and photon all elementary
particles, or are any of these able to be broken down into more
In beta decay, the neutron decays into something else, so maybe it has a
structure. When we throw
1. Analyze the basic operation of a transformer. Determine if a transformer is a step-up or stepdown transformer. Find the output voltage of the secondary coil given the input voltage at the
primary coil and the number of turns in each coil. Find the curr
One way: inertial confinement
Take pellet with hydrogen in it. Hit it with laser beams from many high
energy lasers, so that it heats up so quickly that the hydrogen atoms do not
have time to get away without hitting other hydrogen atoms.
Second way: Magn
1) a) Is there a minimum (other than zero) or maximum x-ray photon
energy from an x-ray machine?
b) Is there a minimum (other than zero) or a maximum photon
wavelength from an x-ray machine?
c) What is this (minimum or maximum) photon ener
You should know how to do the following:
1. Find the size and direction (Force RHR #1) of the magnetic force exerted upon a
charge moving in a magnetic field.
2. Analyze the motion of charged particles moving in electric and/or magnetic
fields. In particu