Lecture 21 - Some physics of materials
Designing structures requires both an understanding of equilibrium and of material properties so that the correct material can be
used in the right place, this will be a question of how well it can tolerate the requi
Lecture 9 - Gravitation
So far we have focused on contact forces. In this lecture we look at a force that acts at a distance, gravity
Newton's Law of Universal Gravitation
Newton's famous, and supposedly apple inspired, idea that the same force that cause
Lecture 5 - Newton's Laws of Motion
In the lectures up till now we have been discussing kinematics, the description of motion. Now we start to
explore the dynamics of motion, introducing the key concept of force and Newton's Laws of Motion.
Godfrey Knelle
Lecture 8 - Circular Motion
Uniform circular motion - Frequency and period
Frequency (revolutions per second) f [ s 1 or Hz]
Period (time for one revolution) T
Velocity v
=
2r
T
=
1
f [s]
= 2rf [ms 1 ]
Newton's First Law
Every object continues in its stat
Lecture 7 - Friction, drag and terminal velocity
In this lecture we will cover forces that resist motion, friction and drag. These forces are inherently complicated
and the models we will cover are highly simplified. They do however allow us to get substa
Lecture 3 - 2 and 3 dimensional kinematics
In this lecture we look at vectors in 2 and 3 dimensional motion and study a specific example of 2
dimensional motion - projectile motion.
Vectors and scalars
Vector quantities with number, direction and units:
D
Lecture 2 - 1D Kinematics
Kinematics [http:/en.wikipedia.org/wiki/Kinematics] describes the motion of an object without looking at it's underlying
causes. We'll come back to those causes (forces) when we start to study
dynamics [http:/en.wikipedia.org
/wi
Lecture 4 - Solving Kinematics problems
In this lecture we will discuss problem solving approaches for kinematics.
Starting Point
Draw a diagram
Identify variables and relevant equations
Identify known and unknown quantities
Come up with a strategy to get
Lecture 6 - Applications of Newton's Laws
Free-Body Diagrams
Free-body diagrams are used to represent all the forces on an object to determine the net force on it. They are termed free-body
diagrams because each diagram considers only the forces acting on
Lecture 13 - Gravitational Energy and Power
Total Energy Conservation
Non conservative forces remove mechanical energy from the system, but it is not destroyed, it is simply converted to a
different form of energy (frequently, but not always, heat).
The t
Lecture 12 - Conservation of Energy
The Law of Conservation of Energy
The law of conservation of energy states that within a closed system the total amount of energy is always conserved.
Another way of this is saying this is that energy can be neither cre
Lecture 16 - Rotational Kinematics
So far most of our moving objects have been sliding. In the translational motion of a sliding object all points maintain a constant
displacement from the center of mass of the object. But what about a point on a rolling
Lecture 17 - Rotational Dynamics
Torque
In the same way as a force causes linear acceleration, F = ma , there must be an analogous quantity and equation related to
angular acceleration. From experience, for example when we use a wrench (or a spanner in ci
Lecture 18 - Angular Momentum
Angular Momentum
Linear momentum
p = mv
By analogy we can expect angular momentum is given by
L = I
Units kgm 2 /s
Newton's Second Law for translational motion
F = ma =
dp
dt
By analogy we can expect Newton's Second Law for
Lecture 15 - Linear momentum in more than one
dimension
Inelastic collisions
A bullet hitting an object is a good example of an inelastic collision.
Ballistic Pendulum
We can however use conservation of momentum for the collision and conservation of energ
Lecture 11 - Work and Energy
In this lecture we introduce the concept of the work done by a force, and relate this to the kinetic energy of an object.
Work
Work is a measure of what a force achieves, so when we calculate the work done by a force on an obj
Lecture 14 - Linear Momentum and One Dimensional
Collisions
Momentum is an extremely useful quantity. Conservation of momentum is one of the most fundamental laws of the universe!
Momentum
We can define momentum as the mass times the velocity
p = mv
Momen
Lecture 10 - Orbits
The first artifical satellite Sputnik.
Satellites
For a circular orbit a satellite of mass m must have a velocity such that the gravitational acceleration is the same as the
centripetal acceleration.
G
mME
r2
=
mv 2
r
v circular = GME
Lecture 20 - Static Equilibrium
Equilibrium describes a state where both the linear acceleration and angular acceleration of an object or system are zero.
This means the object is either at rest or moving with constant velocity.
Here we will focus on situ
Lecture 19 - Advanced Rotational Motion
The gyroscope
As we saw with a spinning bike wheel it takes a large torque to reorient a large angular momentum vector. If a spinning
object is mounted so that it is free to orient itself in any direction, as it is
Lecture 28 - Wave effects
Lots of Java applets for visualizing waves can be found at http:/www.falstad.com/mathphysics.html. I'll be
using them today and you may find them fun to play with yourself!
Reflection and transmission
A one dimensional pulse on a
Lecture 27 - Waves
Waves are a way that energy can be transported through a medium without the medium moving itself.
Pulses
Suppose we consider a 1 dimensional medium to be a number of masses connected to each other by springs.
The Shive Wave Machine is e
Lecture 26 - Not so simple harmonic motion
Equations of motion for SHM
Starting from Newton's 2nd Law
ma = F
m
d2 x
dt 2
= kx
Based on our previous observations we might guess that the displacement will be able to be expressed as
trigonometric function of
Lecture 23 - Fluids in Motion
In this lecture we look at fluid dynamics, the study of fluids in motion.
Laminar vs. Turbulent Flow
A smooth flow of a fluid is called laminar flow. Flow at higher velocities frequently becomes turbulent.
Most of this lectur
Lecture 25 - Simple Harmonic Motion
We will now begin to consider oscillatory motion, beginning with the simplest example, simple harmonic motion.
Restoring force of a spring
A vertical spring
A vertical spring will also execute simple harmonic motion, th
Lecture 24 - Midterm II Review
Newton's Laws
1. Every object continues in its state of rest, or of uniform velocity in a straight line, as long as no net force acts on it.
2. F = ma
3. Whenever one object exerts a force on a second object, the second exer
Lecture 22 - Static Fluids
Phases of Matter
Solids - Will maintains a fixed shape and will not flow.
Liquids - Does not maintain a fixed shape, will flow, but is not readily compressible.
Gases - Does not maintain a fixed shape, will flow, and will expand
Lecture 31 - Temperature and Thermal Expansion
Atomic Theory of Matter
To introduce the concept of temperature we need to start from the atomic theory, which considers matter to be composed
of atoms.
A useful unit when discussing the mass of atoms is the
Lecture 29 - Sound
For a great page on music acoustics which I will be using a lot in this lecture: http:/www.phys.unsw.edu.au/music/
A very cool, open source, sound editor: http:/audacity.sourceforge.net/
Properties of Sound
Sound is generated by an osci
Lecture 36 - First Law of Thermodynamics
First Law of Thermodynamics
The first law of thermodynamics, dictates how internal energy, heat and work are related to each other. For a closed system the
first law states that the change in the internal energy of