Announcements 11/22/11 Prayer Lab 10, HW 36 due tonight Typo in problem 36-1: the left hand side of the equation should be and not Exam 3 starts Monday.

Slides:



Advertisements
Similar presentations
Chapter 38A - Relativity A PowerPoint Presentation by
Advertisements

Lecture 20 Relativistic Effects Chapter Outline Relativity of Time Time Dilation Length Contraction Relativistic Momentum and Addition of Velocities.
Cutnell/Johnson Physics 7th edition
Relativity Theories. The Principle of Relativity Although motion often appears relative, it’s logical to identify a “background” reference frame from.
Frames of Reference and Relativity
AP Physics Review Ch 7 – Impulse and Momentum
1 Special Relativity (Ch 37) Modern physics special relativity quantum mechanics Both were developed to explain the “few remaining puzzles” of classical.
Announcements 11/23/10 Prayer Exam 3 review session: Monday 5 - 6:30 pm, room C261 Exam 3 starts Tuesday after break Lab 10 due Tuesday after break.
Announcements 11/29/10 Prayer Exam 3 starts tomorrow! Exam 3 – “What’s on the exam” handout Exam 3 review session tonight, 5 – 6:30 pm, room C261 Lab 10.
Physics 218 Lecture 16 Dr. David Toback Physics 218, Lecture XVI.
Announcements 4/1/11 Prayer Labs 9, 10 due tomorrow Exam 3 starts tomorrow “So, Dr. Colton, what’s on the exam?”
The laws of physics are the same in any inertial (non- accelerating) frame of reference Galileo & Einstein would both agree (at terrestrial speeds.) F=ma.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 26: Relativity.
Announcements 11/28/11 Prayer Exam 3 ongoing, ends on Saturday Next Wednesday: Project “Show & Tell” a. a.I’ll pick 4 groups to do 10 min presentations.
Special Relativity & General Relativity
Chapter 37 Special Relativity. 37.2: The postulates: The Michelson-Morley experiment Validity of Maxwell’s equations.
Announcements 4/4/11 Prayer Exam 3 ongoing Project final reports & “Show & Tell”
Physics 218, Lecture XIV1 Physics 218 Lecture 14 Dr. David Toback.
Further Logistical Consequences of Einstein’s Postulates
Dr. Michael Cooke Dr. David Schmitz Fermilab. Newton’s Laws of Motion o o 1. Objects in motion want to stay in motion and objects at rest want to stay.
Special Relativity Physics 1161: Lecture 35 Sections 29-1 – 29-6.
Quiz Question What is an “intertial” reference frame? A.One in which an object is observed to have no acceleration when no forces act on it. B.One in.
Outline - Feb. 8, 2010 Postulates of special relativity State of Motion Reference Frames Consequences of c = constant Time dilation and length contraction.
Planet Earth Einstein’s Theory of Special Relativity.
Can momentum change? ∆p = m ∆v Change in momentum = mass x change in velocity (Units) kgm/s = kg x m/s ∆p = m ∆v Change in momentum = mass x change in.
Chapter 26 Michelson-Morley Continued Relativistic Energy and Momentum.
Introduction to special relativity
Special Theory of Relativity
Page 1 Phys Baski Relativity I Topic #9: Special Relativity I Transformation of Variables between Reference Frames –Non-relativistic Galilean Transformation.
Special Theory of Relativity Space and Time. Inertial reference frames Reference frames in which Newton’s first law is valid. –In other words, a reference.
Chapter 27 Wave/Particle Exp. Chapter 26 Relativity Intro.
Welcome to our Special Relativity Minicourse Brought to you by Quarknet Physics Department of the University of Houston Physics and Astronomy Department.
The Special Theory of Relativity. Galilean-Newtonian Relativity Definition of an inertial reference frame: One in which Newton’s first law is valid Earth.
Announcements 11/26/12 Prayer Exam 3 ongoing, ends on Saturday Review session: today 4:30-6 pm, in this room Next Wednesday: Project “Show & Tell” a. a.I’ll.
 Newtonian relativity  Michelson-Morley Experiment  Einstein ’ s principle of relativity  Special relativity  Lorentz transformation  Relativistic.
Announcements Homework Set 1 is due now. I will accept the homework if placed in my mailbox by 5:00pm today Solution to HW Set 1 will be posted soon (Friday?)
Announcements Exam 3 is Monday April 13. Will cover the rest of Chapter 4, all of Chapters 5, 6, 7 & 8. New Sample Questions that include Chapter 8 are.
Special Relativity: “all motion is relative”
Announcements 11/20/12 Prayer Lab 10, HW 36 due tonight Exam 3 starts Monday after break Exam 3 review: Monday, 4:30 – 6 pm, this room Close to Home.
Special Relativity: Time Dilation and Length Contraction SPH4U.
Einstein’s Special Relativity. Postulates 1. The speed of light is a universal constant 2. All laws are the same in any inertial reference frame.
Physics 2170 – Spring Einstein’s theory of special relativity First homework assignment is online. You.
The Theory of Special Relativity Ch 26. Two Theories of Relativity Special Relativity (1905) –Inertial Reference frames only –Time dilation –Length Contraction.
Physics Lecture 2 1/26/ Andrew Brandt Monday January 26, 2009 Dr. Andrew Brandt 1.Special Relativity 2.Galilean Transformations 3.Time.
Welcome to our Special Relativity Minicourse Brought to you by Quarknet Physics Department of the University of Houston Physics and Astronomy Department.
Modern Physics Relativity 1 Space is defined by measurements of length and depends on what “ruler” is used to measure the length. Time is defined by measurements.
Dr. Michael Cooke Dr. David Schmitz Fermilab
Introduction to special relativity
Special Relativity I wonder, what would happen if I was travelling at the speed of light and looked in a mirror?
Astronomy 1143 – Spring 2014 Lecture 18: Special Relativity.
Physics 218 Lecture 15: Momentum Alexei Safonov.
Phy 107 Fall From Last Time Physics changed drastically in the early 1900’s Relativity one of the new discoveries –Changed the way we think about.
Physics 102: Lecture 28, Slide 1 Special Relativity Physics 102: Lecture 28 Make sure your grade book entries are correct Bring ID to Final EXAM!!!! Today’s.
IB Physics – Relativity Relativity Lesson 1 1.Galilean Transformations (one frame moving relative to another) Michelson Morley experiment– ether. 2.Speed.
Unit 13 Relativity.
Consequences of Special Relativity Simultaneity: Newton’s mechanics ”a universal time scale exists that is the same for all observers” Einstein: “No universal.
Special Relativity = Relatively Weird
Chapter 39 Relativity. A Brief Overview of Modern Physics 20 th Century revolution 1900 Max Planck Basic ideas leading to Quantum theory 1905 Einstein.
11.1 – Frames of Reference and Relativity
Relativity made simple?. Newton Maxwell The Laws of Physics – the same in all “inertial” frames.
Relativity. Historical Development 1600s Newton discovered his laws of mechanics Applied to a wide variety of problems over the next two decades Worked.
Special Relativity How does light behave in moving reference frames?
Chapter 6. When objects collide their motion changes and this is the result of a concept called momentum. Momentum = mass x velocity p = mv kgm/s or Ns.
Physics 2170 – Spring Galilean relativity Homework assignment will be posted on the web site by 5pm today.
11.1 – Frames of Reference and Relativity. Inertial Frame of Reference (IFOR) a frame of reference in which the law of inertia holds The FOR must be at.
Special Relativity Physics 102: Lecture 28
Physics 1161: Lecture 26 Special Relativity Sections 29-1 – 29-6.
The Galilean Transformations
The Galilean Transformations
Physics 1161: PreLecture 26 Special Relativity 1.
Presentation transcript:

Announcements 11/22/11 Prayer Lab 10, HW 36 due tonight Typo in problem 36-1: the left hand side of the equation should be and not Exam 3 starts Monday after break Close to Home

Optical Modulators Electro-optic modulator Acousto-optic modulator AOM EOM Field changes vertical index of refraction

About the Exam…

Reading Quiz From my point of view, objects which experience no force don’t accelerate. What type of reference frame am I in? a. a.An “Einsteinian” reference frame b. b.An “enlightened” reference frame c. c.An “inertial” reference frame d. d.A “null” reference frame e. e.A “unique” reference frame

Fictitious forces Toss a ball straight up, in car. Slam on the brakes. What happens? Throw a ball to a friend on a merry-go-round (as it’s spinning). What path does the ball take? Reference frames where Newton’s Laws apply: “inertial frames”

Galilean Relativity Credit: this slide and next one from Dr. Durfee v 1 = 80 mph v 2 = 100 mph

Galilean Relativity v 1 = 0 mph v 2 = 20 mph Reference frame moving with car 1

HW 37-3 A 1 kg object (m 1 ) collides with a 2 kg object (m 2 ) on a frictionless surface. Before the collision, m 1 is traveling at 9 m/s to the right and m 2 is at rest with respect to the ground. The collision is elastic and m 1 bounces straight back to the left. a. a.Figure out the final velocities of both masses after the collision. [Hint given.] b. b.A bicycle rider moving at 5 m/s to the right (relative to the ground) observes the collision. Show that both kinetic energy and momentum are also conserved in her frame of reference. All valid physical laws are true in all inertial reference frames

Bike lights I’m riding my bike at 1  10 8 m/s. I turn on my front bike light (c=3  10 8 m/s). a. a.How fast does someone on the ground see the light waves go away? b. b.How fast do I see the light waves go away? Changing magnetic field  electric field Changing electric field  magnetic field Nothing in equations says anything about the flashlight!!! (the source of waves) Maxwell Eqns: speed of waves is

Compare to Sound Source stationary: sound waves travel at 343 m/s (as measured by both source and observer) Source moving at 100 m/s: ?  sound waves still travel at 343 m/s (as measured by both source and observer). Only frequency will be changed. Why is it a Big Deal that light waves do the same thing?

Einstein: There is no problem Postulate 1: The laws of physics apply in all inertial reference frames. Postulate 2: The speed of light is the same for all inertial observers, regardless of motion of the light source or observer. The “Big Deal”: these two simple statements have some crazy implications, as we shall see. Michelson-Morley experiment

Example: Light Ray on a Train If height of train car inside is h, how long did that take (to me, inside the train)? Credit: animations from Dr. Durfee Answer: t = 2h/c

As seen from ground If height of train car inside is h, how long did that take (to you, on the ground)? Train is traveling at speed v Answer: t = 2h/c  (1-v 2 /c 2 ) -1/2 How long did it take, really? Why doesn’t this “problem” exist with sound waves?

Notation Time measured by me, on train:  t Time measured by you, on ground:  t  Answer 2 (measured on ground): t = 2h/c  (1-v 2 /c 2 ) -1/2 Answer 1 (measured on train): t = 2h/c For v = 0.9c:  = 0.9  = 2.3 v/cv/c 

Think about this… Suppose I, Dr. Colton (in the train), measure a time interval to be 1 second, presumably through lots and lots of light bounces or something along those lines. If the train is moving at 0.9c, you, the class (on the ground) measure that time interval to be 2.3 s. To you, it looks like things in the train are running in slow motion. However, what if you on the ground are the one that is bouncing light rays back and forth. If you measure a time interval to be 1 s, how long will that interval look like, to me on the train? a. a.1 s. That is, to Dr. Colton, it looks like things on the ground are running normally b. b.(1/2.3) s. That is, to Dr. Colton, it looks like things on the ground are sped up c. c.2.3 s. That is, to Dr. Colton, it looks like things on the ground are running in slow motion. To you, my time appears to be slowed. To me, your time appears to be slowed. Who is right?

Twin “Paradox” Speedo & Goslo…which twin is older?

Simultaneity Dr. Colton on train, again Turn the flashlights on at the same time, the photons reach the walls simultaneously. OK?

Simultaneity Viewed from the ground; train moving to right. Which light ray travels farther? Which light ray hits the wall first? Events which happen simultaneously in one “reference frame” do NOT happen simultaneously in any other reference frame

A different effect Light from which lightning bolt will reach Jim first? Jim Slide credit: Dr Durfee, again

Jim

Jim’s friends all record the actual times in Jim’s reference frame Or equivalently, Jim is just smart enough to factor out the time the light took while traveling. An “array” of observers Jim Jim’s friends