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Welcome to Physics 7C. Emily West ewest@physics.ucdavis.edu. Agenda . Logistics: Syllabus & Web Page Clicker Setup Course Overview--the big ideas Simple Harmonic Oscillation Review Wave Introduction What is Total Phase and why do we care?. Some Logistics.
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Welcome to Physics 7C Emily West ewest@physics.ucdavis.edu
Agenda • Logistics: Syllabus & Web Page • Clicker Setup • Course Overview--the big ideas • Simple Harmonic Oscillation Review • Wave Introduction • What is Total Phase and why do we care?
Some Logistics • Course Webpage: http://physics.ucdavis.edu/physics7
Clicker Setup: Joining Class • Turn on your clicker; It scans for Classes • If it doesn’t scan automatically, hit enter (green button) • Find FAPHY7C1; hit enter • Display reads “ANS: FAPHY7C1;” hit enter • When you’ve successfully joined, display reads “ANS: wait for Q”
PRS Clicker Setup: Student ID • Turn on your clicker • Press * to access Setup Menu • Scroll to find “ID;” hit Enter (green button) • Enter your Student ID so I can give you credit; hit enter
Check Clicker Setup • In DL on Thursday, Friday, or Monday we talked about… A) Three-phase diagrams and the heat pack B) Waves and Oscillators C) Steady-state flow in a fluid circuit D) Slow down--I didn’t get my ID entered yet!
Big Ideas of 7C • Wave Model • Interference • Ray Model • Optics • Field Model • Electricity • Magnetism • Quantum Mechanics
Simple Harmonic Oscillation Review How can we describe the motion of oscillating objects?
Simple Harmonic Motion (SHM) Constructs • Amplitude: maximum distance from equilibrium • Period (or frequency): amount of time required to complete a cycle (or number of cycles per unit time) • Equilibrium: position at which all forces acting on the object sum to zero. • Displacement: position of the object relative to equilibrium • Restoring Force: a force that acts on an object that tends move it toward equilibrium • Defining SHM: The restoring force is proportional to the displacement. • Anything missing?
Mathematics of SHM y=Displacement A=Amplitude T=Period y t
Mathematics of SHM y=Displacement A=Amplitude T=Period y 1 6 4 In this image, which numbers, if any, show… Displacement? t 3 2 5
Mathematics of SHM y=Displacement A=Amplitude T=Period y 1 6 4 In this image, which numbers, if any, show… t 3 2 5 Amplitude?
Mathematics of SHM y=Displacement A=Amplitude T=Period y 1 6 4 In this image, which numbers, if any, show… t 3 2 5 Period?
Mathematics of SHM y=Displacement A=Amplitude T=Period y A In this image, what is the mass doing at t=0 seconds? t T A Is the equation correct as is? T y(t) = A sin (2p t/T)???
Mathematics of SHM y y=Displacement A=Amplitude T=Period T f=phase t In this image, what is the mass doing at t=0 seconds? A In this image, what value does fhave? y(t) = A sin (2p t/T + f) y(t) = A sin (2p t/T)?
Making Waves • Watch waves • How does the motion you are watching differ from the motion of the mass-spring? • How is it the same? • What new constructs are needed to describe waves? • What constructs can I control when I start the wave? How do I change each one? • What moves from one end of the machine to the other?
Wave Constructs • Waves: A transfer of energy without bringing along the mass. • Particles in the medium get disturbed and collide, but they stay oscillating about one position; they don’t travel with the wave. • The medium does not effectively move. The disturbance advances, that’s the wave.
Graphing Waves a) At a particular time (holding position constant) b) At a particular position (holding time constant)
Mathematics of Harmonic Waves • Displacement (y) is a function of both position along the medium and time. y(x,t) • In space, function repeats every wavelength • In time, function repeats every period
Longitudinal vs. Transverse Wave Polarization ` Longitudinal Wave Transverse Wave