PHYS1120PodcastLecture26Transcript
4.
Here is an example.
A dust particle with mass m = 5 * 10-9 kg and a charge of 2.0 nC starts at rest at point a and moves in a
straight line to point b.
What is its speed at point b?
5.
Here is the solution.
Let us beg
PHYS1120PodcastLecture40Transcript
4.
On a cold clear night, if you are high in the northern hemisphere, say Alaska, you might be able to see a great
light show above your head. That light show is known as the Aurora Borealis, but it is also called The
No
PHYS1120PodcastLecture42Transcript
4.
Here is an example.
Beginning with the conservation of energy, derive the equation for the mass to charge ratio (m/q) as a
function of magnetic field strength B, potential V, and radius of motion r.
5.
Here is the sol
PHYS1120PodcastLecture37Transcript
4.
In circuits with multiple loops, one must do the following things:
1. Look at how many loops can be made.
2. Draw the loops and note the direction.
3. Sum the voltages in each loop (remember KLR, they have to equal 0)
PHYS1120PodcastLecture33Transcript
4.
Here is an example.
A lightbulb is rated at 120 Volts and 75 Watts.
1. What is the current through the bulb?
2. What is the resistance of the bulb?
5.
Here is the solution.
A lightbulb is rated at 120 Volts and 75 Wat
PHYS1120PodcastLecture39Transcript
4.
This slide has the representation of charge and current as a function of two things: Time, and the time
constant. The time constant is the Greek letter Tau. Tau = RC. Now, you can sort of see the basic form of
familia
PHYS1120PodcastLecture35Transcript
4.
Preamble.
So I had originally placed a really big circuit example here as a lecture. While I do like giving examples,
the nature of this podcast is structured to discuss a topic qualitatively, and to give several corr
PHYS1120PodcastLecture34Transcript
4.
Here is an example.
You have a circuit of three resistors and a battery.
V =18 volts, R1 = 4 Ohms, R2 = 6 Ohms, R3 = 3 Ohms,
1. Find the total resistance.
2. Find the total current going through the equivalent resisto
PHYS1120PodcastLecture36Transcript
4.
The simple circuits we have dealt with thus far can be analyzed with Ohms Law, and rules for parallel and
series circuits.
Some of the more complex circuits involve multiple batteries and junctions.
There are two rule
PHYS1120PodcastLecture31Transcript
4.
Resistivity has a temperature dependence.
Resistivity has its origin in collisions between electrons and atoms or molecules.
Higher temperature = faster thermal velocities = more collisions = higher resistivity.
We ca
PHYS1120PodcastLecture29Transcript
4.
Does it ever make sense to put capacitors in series?
You get less capacitance and less charge storage than with either alone.
Why not just put it in parallel?
Series is sometimes done in electronics because capacitors
PHYS1120PodcastLecture27Transcript
4.
How can you increase the effectiveness of a capacitor? As we have seen, the geometry comes into play. If
the area of the capacitor is big, then so will be the capacitance. You can also shrink the distance between the
PHYS1120PodcastLecture25Transcript
4.
For potential energy, we first learned about it in Physics 1. Potential energy is a measure of energy content
that depends on the mass of the object, its distance from the ground, and the value of acceleration. The
re
PHYS1120PodcastLecture32Transcript
4.
An electromotive force (emf) is a source of energy in a circuit that causes charges to move.
It is the influence due to a non electrical process that makes charges gain potential and make the flow go
from low to high
PHYS1120PodcastLecture38Transcript
4.
What is an RC circuit?
RC circuits can be used to filter a signal by blocking certain frequencies and passing others.
These circuits can be found in loud speaker systems.
RC and other filters are widely used in select
PHYS1120PodcastLecture30Transcript
4.
Resistance is a measure of how easily current flows in a material.
It depends on Voltage (V) and current (I)
We define resistance as: R = V/I
This is Ohms Law.
For the same voltage, more resistance means less current,
PHYS1120PodcastLecture41Transcript
4.
Here is an example.
A neutron star is the leftover remnant from a star that underwent a supernova explosion.
This object is made of neutrons, and has a magnetic field strength of B = 108 Teslas.
Typical neutron star s
PHYS1120PodcastLecture28Transcript
4.
Eventually, we may have more than 1 capacitor in our system. Perhaps we have several capacitors arranged
in a parallel connection. When we have a parallel connection, that means that our initial current path can split
Login for homeworks on www.masteringphysics.com
PHYS 1120
Dr. Andrew Young
PHYS 1120
Lecture 01
Upcoming Agenda
Zeroth Law of Thermodynamics
Previously in Physics 1
The general discussion on energy involved two major
types: kinetic and potential.
Kinetic
Login for homeworks on www.masteringphysics.com
PHYS 1120
Dr. Andrew Young
PHYS 1120
Lecture 03
Upcoming Agenda
Greenhouse Effect, Thermal Expansion
Temperature and Thermal Equilibrium
Some Thermometers:
Atmospheric Greenhouse Effect
Greenhouse Gases:
Car
Login for homeworks on www.masteringphysics.com
PHYS 1120
Dr. Andrew Young
PHYS 1120
Lecture 02
Upcoming Agenda
Convection, Temperature, Thermometer
Convection
Matter receives energy, but that energy is not released back into the surroundings
quickly eno
Login for homeworks on www.masteringphysics.com
PHYS 1120
Dr. Andrew Young
PHYS 1120
Lecture 08
Upcoming Agenda
Ideal Gas Law
The Ideal Gas Law
The ideal gas law can be written as pV=nRT
T is your temperature in Kelvin.
P is your pressure in Pascals (whic
Login for homeworks on www.masteringphysics.com
PHYS 1120
Dr. Andrew Young
PHYS 1120
Lecture 09
Upcoming Agenda
RMS Speed, Internal Energy
The Meaning of Temperature
Internal energy U is related to pressure and volume.
It is also related to temperature:
a
Login for homeworks on www.masteringphysics.com
PHYS 1120
Dr. Andrew Young
PHYS 1120
Lecture 05
Upcoming Agenda
Specific Heat, Latent Heat of Fusion, Latent Heat of Vaporization
Example
You have an empty 20-kg cauldron made of iron.
1. How much heat inp
Login for homeworks on www.masteringphysics.com
PHYS 1120
Dr. Andrew Young
PHYS 1120
Lecture 04
Upcoming Agenda
Thermal Expansion, Heat Flow, Heat Capacity
Example
A steel bridge is 600 meters long.
How much allowance must be made for linear action if
T g
Login for homeworks on www.masteringphysics.com
PHYS 1120
Dr. Andrew Young
PHYS 1120
Lecture 06
Upcoming Agenda
Blackbody Radiation, Heat Transfer Rate
Latent Heat of Fusion/Vaporization
Blackbody Radiation
Objects that become sufficiently hot will glow v
Login for homeworks on www.masteringphysics.com
PHYS 1120
Dr. Andrew Young
PHYS 1120
Lecture 11
Upcoming Agenda
Work, First Law of Thermodynamics
Work Done by Thermal Systems
Work can be done by, instead of on, thermal systems,
as in the expansion of a ga
Login for homeworks on www.masteringphysics.com
PHYS 1120
Dr. Andrew Young
PHYS 1120
Lecture 10
Upcoming Agenda
RMS Speed, Internal Energy
Example
What is the average kinetic energy of molecules in a
gas if the total internal energy is 3852 Joules?
Assume
Login for homeworks on www.masteringphysics.com
PHYS 1120
Dr. Andrew Young
PHYS 1120
Lecture 07
Upcoming Agenda
Charless Law, Boyles Law, Atomic Terminology
Example
Lets say that as you jog, you generate this heat
Q = 8*105 Joules
As a 65 kg jogger, the s
Login for homeworks on www.masteringphysics.com
PHYS 1120
Dr. Andrew Young
PHYS 1120
Lecture 12
Upcoming Agenda
Heat and Work, Carnot Efficiency, Combustion
Heat and Work
Heat flow Q is positive when the system gains heat.
Heat flow Q is negative when t