A spring is stretched from x=0x=0 to x=dx=d, where x=0x=0 is the equilibrium position of the spring. It is then compressed from x=0x=0 to x=−dx=−d. What can be said about the energy required to stretch or compress the spring?

Ablue car pulls away from a red stop-light just after it has turned green with a constant acceleration of 0.5 m/s 2 . a green car arrives at the position of the stop-light 6.5 s after the light had turned green. if t = 0 when the light turns green, at what time does the green car catch the blue car if the green car maintains the slowest constant speed necessary to catch up to the blue car? answer in units of s.