1. A position vector is given by ~r(t) = 10m+ 5 m/s tˆj. What is the displacement in the interval between t=0.0s and t=2.0s? 2. What is the period of a rock of mass 2.0kg tied to the end of a spring 0.625m long string that hangs in a doorway and has an elastic constant of 40N/m?

3. Draw a phase portrait for an oscillating, damped spring.

I don't understand how to do these 3 questions

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 = ?