Non conservative force energy that we are losing from the system, that we can’t get back. It’s conserved on a
universe scale
Why choose the dot product operator for power? why not cross product? (P=F∗v)
Work done is distance covered against an opposing force
Triboelectric materials have a stronger tendency to give up their electrons, the binding forces (?) aren’t as
strong.
Torsion, twisting in string is related to angle change, the force it tries to counter this with
27/09/22 10:00:37
problem sets due Friday week (7th Oct)
29/09/22 14:41:15
Cow’s can get an electric shock from lightning because of a potential difference between their front and rear.
03/10/22 12:04:15
Potential is a scalar
Force per unit charge (electric field)
electrons moving through lattice (like, say copper) are resisted by structure of lattice
Why don’t electrons just accelerate indefinitely
Electron conductivity has much larger range than thermal conductivity. There are certain materials that can
pretty much stop electron flow (in our time span). The same can not be said for heat.
Electron current generates a wavefront. The electrons themselves aren’t travelling that fast just pushing the
ones on front of them (longitudinal wave)
Free carrier density is total number of electrons that have the ability to move around
Finite rod in a magnetic field. Finite time of movement of charge
04/10/22 10:02:29
lump circuitry, resistor drawn as potion of wire but actually represents resistance in the whole wire.
Voltage, joules per coulomb that’s energy given to charge
Magnetism, not discussing sources of these fields yet. Chpt 27 and 28 of book
Non uniform magnetic field tends to cause oscillation?
Electric fields generated by static particles, magnetic fields generated by moving particles
Not entirely clear how to multiply two vectors. Are vector operations emergent form experience or is it a
mathematical construct that seemed to fit nature. X cross Y equals Z, used in coordinate systems
magnetic field changes direction of motion but done no work on the particle. Electric potential is reduced on
accelerating a charge.
10/10/22 11:58:00
Sources of magnetic fields
Loop of current diagram is kind of a thought experiment
Loop will rotate until flat with field
Loop can gather a potential if it’s held
Model clouds of electrons as loops of current. Net direction to electrons results in dipole moment, meaning they
will be attracted or repelled by magnets
There’s a magnetic field that surrounds a moving charged particle. Of different magnitudes, like a bubble
example 3.5 b) x=sqrt(3)a
11/10/22 09:51:59
Magnitude of voltage proportional to the rate of change of the magnetic field