Chapter 27: Relativity © 2016 Pearson Education, Inc.

Goals for Chapter 27 To explain relativity and simultaneity in terms of our experience. To apply relativity specifically to time. To see the relativity of length. To use the Lorentz transformation to see how travel near v = c changes observables. To explain how relativistic momentum and energy make travel at c impossible with technology as we know it today. To study how relativity interacts with Newtonian mechanics. © 2016 Pearson Education, Inc.

A Simple Demonstration Einstein may not be known for being competitive with Heifetz on the violin BUT he is known for his thoughts on relativity. We should master some bullet points from his theory as delineated on page 859. Note especially the boldface terms and 3 major points of inertial reference frames. © 2016 Pearson Education, Inc.

Physical Laws are Invariant – Figures 27.1 and 27.2 Einstein began by asserting that physical behavior was the same in all reference frames. Two examples are shown: kinematics below and electromagnetic induction at right. © 2016 Pearson Education, Inc.

Two Ideas That Will Soon Clash The speed of light is always the same. Velocities are additive in different reference frames (i.e., a person walking on a moving boat looking at a person walking at the same pace on the riverbank). See Conceptual Analysis 27.1 © 2016 Pearson Education, Inc.

Simultaneity – Figure 27.4 A lightning flash observed from the front and back of a moving train by a moving observer helps us to begin setting up the enigma. © 2016 Pearson Education, Inc.

The Light Clock – Figure 27.5 A "light clock" will help us to examine differences in time in this Gadunkin experiment. See Conceptual Analysis 27.2. © 2016 Pearson Education, Inc.

Time Dilation – Figure 27.7 The figure is used in Example 27.1. Refer to Equation 27.6 on page 865. © 2016 Pearson Education, Inc.

Jetliner Time Dilation – Figure 27.8 Refer to Example 27.2 You may not notice the effect on your wristwatch. © 2016 Pearson Education, Inc.

Space Travel and the Twin Paradox This is arguably the most famous example of time dilation. One brother leaves earth and travels a short time near c (perhaps a 5 year mission like Captain Kirk). When he returns home, he mistakes his brother for his grandfather. Read page 868. © 2016 Pearson Education, Inc.

Length Contraction – Figure 27.9 Refer to Equation 27.9. Notice the same velocity fraction as the time dilation problem. It will be designated by gamma. © 2016 Pearson Education, Inc.

A Shrinking Spaceship – Figure 27.10 See Example 27.3 and Quantitative Analysis 27.3. © 2016 Pearson Education, Inc.

The Lorentz Transformation – Figure 27.13 Refer to the yellow boxed equations on pages 913 and 914 and the Problem-Solving Strategy 27.1. © 2016 Pearson Education, Inc.

Relativistic Velocities – Figure 27.14 See Examples 27.4 and 27.5. © 2016 Pearson Education, Inc.

Relativistic Momentum – Figure 27.15 Refer to Quantitative Analysis 27.4. © 2016 Pearson Education, Inc.

Relativistic Momentum – Figure 27.17 Refer to Example 27.8 on page 882. The Stanford Linear Accelerator can move a proton to 0.99c where relativistic effects may be clearly seen. © 2016 Pearson Education, Inc.

Experimental Effects on Diffraction – Figure 27.18 Notice that energy soars exponentially to infinity at c. © 2016 Pearson Education, Inc.

Electronic Energies – Figure 27.19 Refer to Examples 27.7 and 27.8. The figure at right belongs to Example 27.8. © 2016 Pearson Education, Inc.

Relativity and Newtonian Mechanics – Figure 27.20 Without outside references, the astronaut can't tell what is happening outside the capsule. Curved space allows a real test of relativistic effects on objects we can readily observe. insert fig 27.20 and 27.21 © 2016 Pearson Education, Inc.