Aball rolls down a hill with a constant acceleration of 3.0 m/s.
a. if it starts from rest, what is its speed at the end of 4.0 s?
b. how far did the ball move in that 4.0 s?

Point charges q1=+2.00μc and q2=−2.00μc are placed at adjacent corners of a square for which the length of each side is 1.50 cm . point a is at the center of the square, and point b is at the empty corner closest to q2. take the electric potential to be zero at a distance far from both charges. part a what is the electric potential at point a due to q1 and q2? express your answer with the appropriate units.