Good afternoon, I would like to know if you could help me with this Physics exercise.

A point charge q1 = +5.00 mC is fixed at space. From a horizontal distance of 6.00 cm, a small sphere with mass equal to 4.00 * 10-3 kg and charge q2 = +2.00 mC is dis- It stops toward the fixed charge with an initial speed of 40.0 m>s. It is ignored the gravity. What is the acceleration of the sphere at the instant when its speed is 25.0 m>s?