From key@physics.utoronto.ca Sun Feb 24 23:00:42 2008 Date: Sun, 24 Feb 2008 23:00:34 -0500 From: Tony Key To: aasiya.shaikh@utoronto.ca Bcc: key@physics.utoronto.ca Subject: Re: Mastering physics Hi Aasiya - Use energy conservation,. Equate the potential energy of the alpha in the field of the nucleus at r (q1*q2/4*pi*r*epsilon_0) to its kinetic energy (1/2(mv^2)) - remember that the alpha particle has a mass m = 4 times that m_p, and a charge of q2 = 2e. The Au nucleus has a q1 = 79. (The answer you quote below misses a m_p in the denominator). Hope that helps, TonyK aasiya.shaikh@utoronto.ca wrote: > Hi, this is Aasiya Shaikh, one of the students from physics 138. I just > had a question about the mastering physics problem set which is due on the > 29th of Feburary. My question is about the mastering physics problem > worth 10 points. I cant seem to understand why the answer is > 79e^2/4(pi)v^2(E0) because I can't get that answer. It would be much > appreciated if you could explain to me why this is the answer. > Thank you and i hope you reply back, > Aasiya Shaikh >