A 1.8 kg mass oscillates on a spring hanging from the ceiling. If the speed of the mass is 1.4 m/s as it moves through its equilibrium position, what is the potential energy of the system when totally compressed?

After a big snowfall, you take your favorite rocket-powered sled out to a wide field. the field is 195 m across, and you know that your sled accelerates at a rate of 3.65 m/s2 when the rocket is on. how much time will it take the sled to cross the field starting from rest, assuming the rocket is on the whole time?

Idon’t quite understand this problem

Explain what it means to view something from a frame of reference. provide an example that illustrates your explanation. (4 points)