Relativistic Collision An electron with kinetic energy K = 1.000 MeV makes a head-on collision with a positron at rest (a positron is the anti-matter version of an electron with the same mass but opposite charge). After colliding, the two particles annihilate and emit two y rays of equal energy (rays are high energy photons), moving in directions separated by an angle 0.

(a) Why is it not possible for a single ray to be emitted? Hint: Consider the frame of reference of the center of mass of the electron and positron.
(b) Find the energy and momentum p for the emitted rays (in MeV and MeV/c, respectively)
(c) Calculate the electron momentum before the collision.
(d) From the momentum conservation law, derive the angle 8 between the two y rays.

You are a researcher for a golf club manufacturer. you are given two identical looking cubes of a metal alloy. you are informed that they are made of the exact same material, but one is crystalline, whereas the other is amorphous. it is your job to determine which one is amorphous this one is more stress-resistant and is useful in reinforcing golf clubs. which of the following is the best way to determine which is which? a. determine the density of each cube. the more dense one is the amorphous solid. b. melt both cubes and look for a broader range of melting temperatures. the one that melts over a broader range of temperatures is the amorphous solid. c. determine the density of each cube. the less dense cube is the amorphous solid. d. melt both cubes and measure the range of melting temperatures. the one that melts over a narrower range of temperatures is the amorphous solid.