Q. A 10cm-long thin glass rod is uniformly charged to +50 nC. A small plastic bead, charged to - 5.0 nC, is 4.5 cm from the center of the rod. What is the magnitude of the force on the bead?

Q. A 72-kg man stands on a spring scale in an elevator. Starting from rest, the elevator ascends, attaining its maximum speed of 1.20 m/s in 0.80 s. It travels with constant speed for the next 5.00 s. The elevator then undergoes a uniform acceleration in the negative y direction for 1.50 s and comes to rest. What does the the spring scale register (a) before the elevator starts to move?, (b) during the first 0.800 s?, (c) while the elevator is traveling at constant speed?, (d) during the time it is slowing down?