## Lecture 13: Relativistic Conservation Laws

October 5, 2017

• Study: Ex 1; Fig 5.3

### Objectives

• (Continuing objective) Relate the concepts of relativity, momentum, and oscillations to “everyday” situations and discuss various applications of the concepts to practical problems in various fields of science, medicine and engineering.
• Apply the relativistic conservation laws to “explosions,” in which one particle decays into two particles, including cases in which one or both outgoing particles have zero mass.
• Apply the conservation laws to collisions with all particles traveling along a line.
• Describe the processes of nuclear fusion and fission, and explain how these processes result in energy production.
• Given information about nuclear masses, calculate the amount of energy released (that is, kinetic energy gained) in a fusion or fission process.
• Given a graph of average mass per nucleon vs. nucleon number, explain how fusion reactions release energy for small nuclei, while fission reactions release energy for large nuclei.

### Homework

• Friday's Assigned Problems: A37, A38, A39; Supp CH 5: 1, 2, 5, 7, 10, 11
• Hand-In Problems due THURSDAY October 12 at 9:30 AM: A36; Supp CH 4: 4, 9, 11, 13, 15; Supp CH 5: 3, 8, 9, 12

### Videos of example problems

To see the problem statement, click on the link below. To play the video example, click on the underlined words "Video Demonstration" near the top of the page with the problem statement.
• Video Example #1: Applying relativistic conservation laws, complete with ugly algebra. Note: the pion and the photon produced after the collision both move to the right. ans: pion energy = 150 Mev, photon energy = 130 MeV
• Video Example #2: Proton-Proton collision. ans: u1/c = 31/2/2, u2 = u1.

### Pre-Class Entertainment

• Jealous Guy, by John Lennon
• Kiss From a Rose, by Seal
• Kodachrome, by Paul Simon