A point charge q1q1 is held stationary at the origin. A second charge q2q2 is placed at point aa, and the electric potential energy of the pair of charges is +5.4×10−8J+5.4×10−8J. When the second charge is moved to point bb, the electric force on the charge does −1.9×10−8J−1.9×10−8J of work. What is the electric potential energy of the pair of charges when the second charge is at point b?

Explanation:

The given data is as follows.

        Electric potential energy () = ?

Formula to calculate electric potential energy is as follows.

                        =

                        =

Thus, we can conclude that the electric potential energy of the pair of charges when the second charge is at point b is .

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min