What is the force of tension in a rope that spins a 250 g object in a vertical circle with a radius of 50 cm if the mass at the top of the loop is traveling at 3 m/s?

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?

What property of an object determines its inertia?

What sort of waves exhibit the doppler effect?