Acceleration of a Sphere with a Charge

[The Matador]

Homework Statement

Two Charged spheres are positioned on a horizontal, frictionless insulating surface, as shown below.

I attached the image at the bottom of the post.

Homework Equations

Coulombs Law and F=ma

The Attempt at a Solution

I plugged in ((8.99 x 10^9)(5.0 x 10^-7)(5.0 x 10^-7))/(1.25)^2

Once I got the answer I used F=ma to find the acceleration which is 9.59 x 10^-2 m/s

I believe this is the correct answer. I was wondering if one of the spheres is negative would I go about answering the question in the same way. Or would I have to factor in other things.

 

[turdferguson]

It sounds like the initial acceleration would only differ in sign, same force, same mass. But there's much more to it, as you may suspect. If you release 2 oppositely charged objects, they will attract toward each other with decreasing distance and increasing force. The acceleration would increase until they collide. For 2 like charged objects, they will repel away from each other with increasing distance and decreasing force. The acceleration will decrease as the force approaches zero, and a final velocity is reached when the objects are at infinity. Because these situations deal with varying force/acceleration, its usually better to think in terms of energy.