60 Week 1: Discrete Charge and the Electrostatic Field
Problem 10.
r = d/2
−e+e
v
v
An electron (charge−e, massm) and a positron (charge +e, massm) revolve around their
common center of mass under the influence of their attractive coulomb force. This bound state
is sometimes called Wikipedia: http://www.wikipedia.org/wiki/positroniumand can actually be
created for very brief periods of time in the laboratory (it is very unstable quantum mechanically as
the positron and electron rapidly anihillate one another). Find the speed of each particlevin terms
ofe,m,kand their separationd. Note well that the circle of their motion has a radiusr=d/2!.