Two uncharged conductors, a and b, are of different sizes. they are charged as follows: 1. a is charged from an electrostatic generator to charge q. 2. a is briefly touched to b. 3. steps 1 and 2 are repeated until the charge on b reaches a maximum value. if the final charge on b is 3q, what was the charge on a after the first time it touched b?

Asolid cylinder is concentric with a straight pipe. the cylinder is 0.5 m long and has an outside diameter of 8 cm. the pipe has an inside diameter of 8.5 cm. the annulus between the cylinder ad the pipe contains stationary oil. the oil has a specific gravity of 0.92 and a kinematic viscosity of 5.57 x 10-4 m2/s. most nearly, what is the force needed to move the cylinder along the pipe at a constant velocity of 1 m/s?