PHYSICS 6 SPRING 2006 HOMEWORK 3 (due Tues. Feb.21) Read : Finish reading the Lightman selection on relativity. Read Feynman, Chapters 1 (to reacquaint yourselves with the atomic/molecular theory of matter) & 4 (read this carefully; energy is fundamental to all we will discuss after E=mc 2 ). Problems: (Problems are to be handed in at the due date.) 1. The charged pion ( π + ) decays into other particles. It has an average decay time of 2.6x10-8 sec. a. If a π + is travelling in a lab at 0.9999c what is its average decay time? b. How far does it travel before decaying (on the average)? c. The π + turns into three particles (usually muon and 2 neutrinos) when it decays. Suppose the muon is produced along the direction of the π + motion and has a velocity of 0.99c in the π + rest frame. What is the muon velocity in the lab? 2. Judy and Andy are twins. Judy gets on a rocket that goes to a star system 20 light years away from earth (as measured from earth, i.e. Andy's frame of reference).
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This note was uploaded on 03/10/2008 for the course PHY 6 taught by Professor Garyr.goldstein during the Spring '06 term at Tufts.