You can see lightning before you can hear the thunder. which is the best explanation for this?
you see the light first because cold air bends the sound waves, but not the light waves, by refraction.
the transmission of light in air is faster than the transmission of sound in air.
diffraction causes the sound to spread out more than the light waves, so you see the light sooner.

Arotating space station is said to create “artificial gravity”—a loosely-defined term used for an acceleration that would be crudely similar to gravity. the outer wall of the rotating space station would become a floor for the astronauts, and centripetal acceleration supplied by the floor would allow astronauts to exercise and maintain muscle and bone strength more naturally than in non-rotating space environments. if the space station is 200 m in diameter, what angular velocity would produce an “artificial gravity” of 9.80 m/s^{2} 2 at the rim?

How can you increase the strength of an electromagnet?

Suppose a wire with a current is pushed upward by a magnetic field. how would the wire move if the direction of the current reversed? explain your answer.