How far apart are two electrons in an electric field?

AI Thread Summary
An electron moving at 3.0 x 10^6 m/s in a uniform electric field of 1000 N/C will decelerate until it comes to rest, with calculations involving its initial velocity and the force acting on it. The discussion also addresses the scenario of two electrons, where the electrostatic force exerted by one electron cancels the gravitational force acting on the other. To solve for the distance between the two electrons, one must equate the gravitational force to the electrostatic force using appropriate formulas. The gravitational force can be calculated using Fg = G m1m2/r^2, while the electrostatic force relies on Coulomb's law. The radius of the Earth is necessary for accurate calculations, which is approximately 6.38 x 10^6 meters.
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1. An electron with a speed of 3.0 x 106 m/s moves into a uniform electric field of 1000 N/C. The field is parallel to the electron's motion. How far does the electron travel before it is brought to rest.

I read the part of the text related to electric fields but I saw nothing that related it to the velocity of particle.

2. An electron is released a short distance above Earth's surface. A second electron directly below it exerts an electrostatic force on the first ele- just great enough to cancel the gravitational force on it. How far below the first electron is the second?

Using Fg = G m1m2/r2 do I use this formula to find out the gravitational force and then set it equal to the electrical force? I'm a little confused on how to approach this.

:-p
Bill
 
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force acting on a charge in a field E is given by F= qE. Use Newtons law to relate the acceleration with this

you know v1, v2, a now find the time

equate the gravitational force between Earth and the electron with the coulomb attraction froce between teh electrons and solve for the r

Hint the distance between the electron and the Earth is not the same as the disatnce between the two electrons i guess the ygeave you radius of the Earth didnt they?)
 
No they didn't give me the radius of the earth. I gave you the entire problem.
 
i guess they expect you to find it out

the radius of the eaarth is 6.38 x 10^6 metres
 
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