The absolute potential at the center of a square is 3. V when a charge of +Q is located at one of the square's corners. What is the absolute potential at the square's center when a second charge of -Q is placed at one of the remaining corners?

A) -6 V
B) -12 V
C) 6 V
D) Zero
E) 12 V

The correct answer is D,    V =0

Explanation:

The electrical potential due to a point charge is given by

        V = k ∑

Let's apply this equation to our case

       V = k (Q / r - Q / r)

       V = 0

Since the two charges have the same magnitude and are of opposite signs and the distance from any corner to the center of the square from side to is

          r =   √2  a/2

Therefore all distances are equal

The correct answer is D

3.2x10^7

what is the speed of a softball that travels 20m in 2secs

speed = 20/2 = 10 m/s