A uniformly charged thin ring has radius 15.0 cm and total charge 23.5 nC. An electron is placed on the ring's axis a distance 30.5 cm from the center of the ring and is constrained to stay on the axis of the ring. The electron is then released from rest. Describe the subsequent motion of the electron. Find the speed of the electron when it reaches the center of the ring.

Two manned satellites approaching one another at a relative speed of 0.550 m/s intend to dock. the first has a mass of 2.50 ✕ 103 kg, and the second a mass of 7.50 ✕ 103 kg. assume that the positive direction is directed from the second satellite towards the first satellite. (a) calculate the final velocity after docking, in the frame of reference in which the first satellite was originally at rest.(b) what is the loss of kinetic energy in this inelastic collision? (c) repeat both parts, in the frame of reference in which the second satellite was originally at rest. final velocity(d) loss of kinetic energy = ?