A point charge q11500 microc is held fixed in space what is

Question

Question: A point charge q1=15.00 µC is held fixed in space. From a horizontal distance of 8.00cm, a small sphere with mass 4.00×10³ kg and charge q2=+2.00 µC is fired toward the fixed charge with an initial speed of 45.0m/s . Gravity can be neglected.

Part A: What is the acceleration of the sphere at the instant when its speed is 23.0m/s?

I want help to determine the acceleration of the sphere at the instant when its speed is 23.0m/s.