
520 Classical Mechanics
© 2010 Taylor & Francis Group, LLC
Example 15.2: The Central Force Motion
The power of the method becomes more convincing if we apply it to central force motion, where
an electron of charge –e revolves about an atomic nucleus of charge Ze.
As the mass of the nucleus is much greater than the mass of the electron, we may consider the
electron evolving about a stationary nucleus without making any appreciable error. Employ polar
coordinates r and θ in the plane of motion to specify the position of the electron relative to the
nucleus (Figure 15.1). The kinetic energy of the electron is
Tmrr
1
222
θ
and its potential energ ...