A pottery wheel, initially at rest, is assumed to be a uniform disk of mass 3.0 kg and radius 20.0 cm. A 25.0 N force is applied tangentially to the rim. What is the angular displacement for this wheel from t=0 to t=30 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.