A 2.0-Coulomb bead is given 20 Joules of electric potential energy by lifting it from the "ground" to point A. If a second bead with twice as much charge, 4.0 Coulombs, is lifted through the same distance, intuitively, how much electric potential energy do you expect it to have at point A?

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".