A POSITIVE POINT CHARGE q1 creates an electric field of magnitude E1 at a spot located at a distance r1 from the charge. The charge is replaced by another positive point charge q2, which creates a field of magnitude E2=E1 at a distance of r2=2r1. How is q2 related to q1? (a)q2=2q1 (b)q2=1/2q1 (c) q2= 4q1 (d)q2 =1/4 q1 (e) q2= sqroot 2 q1

Two steel balls, each of mass m, are welded to a light rod of length l and negligible mass and are initially at rest on a smooth horizontal surface. a horizontal force of magnitude f is suddenly applied to the rod as shown. determine (a) the instantaneous acceleration a of the mass center g and (b) the corresponding rate at which the angular velocity of the assembly about g is changing with time.