Posted by amber on .
Suppose a single electron orbits about a nucleus containing two protons (+2e), as would be the case for a helium atom from which one of the two naturally occurring electrons is removed. The radius of the orbit is 2.65 1011 m. Determine the magnitude of the electron's centripetal acceleration.

physics 
drwls,
V^2/R is the centripetal acceleration. You know the value of R. You can get the velocity V by setting the centripetal force equal to the Coulomb force:
m V^2/R = k Q^2/R^2
In this case, Q = 2e
k is the Coulomb constant.
m is the electron mass and e is its charge.
You will need to look up these numbers. 
physics 
me,
do it yourself :)