In order to attain orbit around earth, the ATLAS-V rocket must accelerate up to a speed of about 7700m/s in about 11 minutes.
a) What average acceleration is required to accomplish this?
b) If the mass of the rocket + fuel is 3.05x105 kg, what is the applied force of the engine?

A0.17kg ball rolls at 0.75m/s to the right on a frictionless surface and collides with a 0.17kg ball rolling to the left at 0.65m/s. (elastic collision) what is the final velocity of the second ball when the first is 0.5m/s to the left? what is the change in kinetic energy before and after?

I'm thinking it's 2 you are asked to explain the earth's magnetic field. which is the best reply? 1. the earth's magnetic south is similar to the north pole of a magnet. 2. the earth's core has a strong magnetic charge similar to the south pole of a magnet. 3. the earth's geomagnetic south is similar to the south pole of a magnet. 4. the earth's magnetic charge is not centered at either pole; it varies based on location.

The force needed to overcome static friction is usually less than that needed to overcome kinetic friction.true or false?