# Homework Help: Circular Motion with a hydrogen atom

1. Nov 16, 2009

### all_relative

1. The problem statement, all variables and given/known data
In the Bohr model of the hydrogen atom, the speed of the electron is approximately 2.01e6 m/s.
Find the central force acting on the electron as it revolves in a circular orbit of radius 4.84e-11 m.

2. Relevant equations

Fc=m*v^2/R

3. The attempt at a solution
I said that the mass was 1.674e-27 kg. If i should use another number, please let me know.

Fc=m*v^2/R
Fc=(1.674e-27)*(2.01e6)^2/(4.84e-11)
Fc=1.39e-4

When I submit this answer to UTexas (an online HW service) it says that I am wrong. I have done this problem several times and keep getting the same thing.

Thanks!

2. Nov 16, 2009

### hage567

You are not using the right value for the mass.

3. Nov 16, 2009

### all_relative

What is the correct value for the mass?
I looked it up on Google and that is what I found.

Thanks.

4. Nov 16, 2009

### hage567

You are looking for the mass of an electron. Is that what you googled?