Answer:
I think sound does not travel at all in space. The vacuum of outer space has essentially zero air. Because sound is just vibrating air, space has no air to vibrate and therefore no sound. If you are sitting in a space ship and another space ship explodes, you would hear nothing.
Explanation:
The answer your looking for is magnetic field
Eight and I don’t know what else to say but for sure 8
Answer:

Explanation:
Given,
Number of turns, N = 645 N
Area, A = 20.25 m²
Earth Magnetic field, B = 5 x 10⁻⁵ T
Maximum Emf = 1.25 V.
Angular velocity, ω = ?
Using Induced Emf formula




Angular velocity of the coil = 
While the boy is sitting on the chair it creates a force downward on the chair and therefore the chair takes it and gives off the equal amount of force. So while he is putting force downward the chair is putting the same force upward.