Speed of two charged, insulated spheres?

[XianForce]

Homework Statement

Two insulating spheres have radii 0.300 cm and 0.500 cm, masses 0.450 kg and 0.700 kg, and uniformly distributed charges of -2.00 µC and 3.00 µC. They are released from rest when their centers are separated by 1.00 m.
(a) How fast will each be moving when they collide? (Hint: Consider conservation of energy and of linear momentum.)

Homework Equations

F = k_eq₁q₂/r²
v = at + v₀
Δs = v₀t + .5at²

The Attempt at a Solution

I found the electrostatic force on the objects. Since they have opposite charges, I know that they move towards each other. I found their accelerations by dividing by their respective masses, and then plugged those into some of the kinematics equations to find the final velocity.

I can see that my methods/assumptions are wrong, I'm just not exactly sure about how to go about this problem.

 

[szynkasz]

Acceleration isn't constant as force increases while spheres get closer

 

[XianForce]

Acceleration isn't constant as force increases while spheres get closer

Yes, but then how do I solve it?

 

[szynkasz]

Your hint says you should use the law of conservation energy and momentum.