1. The problem statement, all variables and given/known data Consider a gas of molecules of mass m at equilibrium at temperature T. Obtain an expression for the fraction of molecules having kinetic energy e = 1/2mC2 in the range e to e + de. This is problem 5.3, page 48 of Vincenti and Kruger's Intro to Physical Gas Dynamics 2. Relevant equations Maxwellian speed distribution 3. The attempt at a solution I'm not sure where to start really, so I don't have much of a solution. If I were finding the fraction of molecules with kinetic energy LESS than 1/2mC2, I would integrate the speed distribution function from 0 to 1/2mC2. But I'm not sure about finding the fraction at exactly 1/2mC2. My first thoughts were to change the speed distribution to an energy distribution by knowing that c2 = 2e/m, and then integrating the kinetic energy distribution from 0 to inf to find the total kinetic energy. Then divide 1/2mC2 by that total to find a fraction. Don't feel like this is right. Anyone care to nudge me in the right direction?