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