Calculating Centripetal Acceleration and Gravitational Force in a Hydrogen Atom

[tuffshorty]

Homework Statement

The mass of an electron is 9 x 10-31 kg. The mass of a proton is 1.7 x 10-27 kg. The proton and electron are about 1.0 x 10-10 m apart in a hydrogen atom. What force of gravitation exists between the proton and the electron of a hydrogen atom? What is the centripetal acceleration of the electron?

Homework Equations

Fg = G*m1*m2/d^2
* Fg is the magnitude of the gravitational force between the two point masses,
* G is the gravitational constant,
* m1 is the mass of the first point mass,
* m2 is the mass of the second point mass,
* r is the distance between the two point masses.

ar = v2 / r

ar is centripetal acceleration
v is velocity in meters per second,
r is the radius of the circle in meters

The Attempt at a Solution

I plugged in the infomation to find the gravitational force and got 1.02051 x 10^-47
but it doesn't give us the nessicary information to find the centripetal acceleration... I don't think.. can anyone help me with this?

 

[Doc Al]

What provides the centripetal force?

 

[tuffshorty]

It rotating around the hydrogen atom I think...

 

[Doc Al]

It rotating around the hydrogen atom I think...

The electron "orbits" the proton. Again, what provides the centripetal force?

 

[tuffshorty]

I suppose I am not sure what you mean.. or what provides it... that is all the question said...

 

[Doc Al]

What force holds the atom together? (It's not gravity.)

 

[tuffshorty]

The electrical charge of the atom?

 

[Doc Al]

The electrical charge of the atom?

Right. The electric force provides the centripetal force. How much is the electrical force? (Hint: Coulomb's law) Once you have the centripetal force, use Newton's 2nd law to find the acceleration.

 

[tuffshorty]

5.508 x 10^-27 N is what i got when i plugged it in...
and for the acceleration i got 6120 meter/second^2

 

[Doc Al]

5.508 x 10^-27 N is what i got when i plugged it in...
and for the acceleration i got 6120 meter/second^2

Please show how you made those calculations.