A fly on the bus????

Question

Has anyone ever noticed a fly on a bus while it was flying? (No pun intended). Especially if the bus was moving? Let's say the bus was going say 30mph. If the fly went from the back of the bus to the front, does that mean the fly is going faster than 30mph?

Also, If you are suspended in the space right in the aisle of a bus, (somehow), and the bus started moving, would you stay in the same position and have the bus hit you or would you move with the bus? This is strange.

Answer 1

The fly is in the air, but on its wing on the air since it is heavier than air.  Grossly, when the bus moves the fly moves.  In detail, if you could measure the fly's acceleration on a graph with the buses, you would find a dip.  If the fly were actively flying forward when the bus accelerated, the dip would be less detectable because it is acting backward on the air.

  If you were suspended, it would depend entirely on how you were suspended.  If you were lighter or as light as air, then you would move forward relative to the bus as it accelerated because the heavier part of the air is shifted back and the line of acceleration "buoyancy" is at an angle.  

If you were suspended by a force field that was vertical to earth's gravity, then when the bus started to move, you would stand still, there being no side forces on you, and the back wall of the bus would hit you when it got there.  If the bus then stopped, you would still have momentum and no braking force, you would travel to the front of the bus and slam into the front wall.

If the force field had automatic side forces, then it would acting just like friction force.

If you were hung by wires, when the bus moved, you would swing back and up from your own inertia and the moving of the mounts and then pendulum back and forth as the bus came to even velocity.