g a small smetal sphere, carrying a net charge is held stationarry. what is the speed are 0.4 m apart

Complete Question

A small metal sphere, carrying a net charge q1=−2μC, is held in a stationary position by insulating supports. A second small metal sphere, with a net charge of q2= -8μC and mass 1.50g, is projected toward q1. When the two spheres are 0.80m apart, q2 is moving toward q1 with speed 20ms−1. Assume that the two spheres can be treated as point charges. You can ignore the force of gravity.The speed of q2 when the spheres are 0.400m apart is.

The value

Explanation:

From the question we are told that

   The  charge on the first sphere is  

    The charge on the second sphere is  

     The  mass of the second charge is

      The  distance apart is  

      The  speed of the second  sphere is  

Generally the total energy possessed by when and   are separated by is mathematically represented

Here KE   is  the kinetic energy which is mathematically represented as

substituting value

And  U is  the  potential  energy which is mathematically represented as

substituting values

So

Generally the total energy possessed by when and   are separated by is mathematically represented

Here is  the kinetic energy which is mathematically represented as

substituting value

And   is  the  potential  energy which is mathematically represented as

substituting values

From the law of energy conservation

So

answer: the answer is a