Why and how do these scenarios happen?

Question

1. A comet in space continues to move without slowing down or slowing up.

2. A large asteroid crashes into the moon.

3. A rocket launches from Earth, leaves the atmosphere, and goes into space.

4. You are standing in a bus that suddenly stops and you keep moving/falling forward.

5. A small asteroid crashes into the moon.

Answer 1

Hi Nicole S.,

Not to get too crazy contemplating all the possible angles, here!

1) Comet in space, no change in speed -- must be moving in a circular orbit around the star, probably very far out (so that no planetary perturbations)

2) large asteroid into Moon - probably pulled out of its orbit by something else, since most deeply-intruding large cometary belt objects in history have already impacted planets

3) Someone wants to get away from Earth, greatly. Rocket is propelled, most efficiently as multi-stage vehicle.

4) You are being carried in your original direction and velocity by your momentum. Get a clue, hang on next time!

5) again, probably pulled from cometary belt by other objects nearby. Because there are many more small objects than large ones in the asteroid belts, this is probably a more frequent occurrence that (2). You can (and should) look up "accretion rate of interplanetary dust" for Earth. It's higher that you might think! (So, why don't we see it happening, at night?).