The correct answer is B, widespread pollution. If you look closely, you can see that the other answers are not problems at all, but benefits! :)
When an elevator is accelerating downward, the normal force is equal to mg-ma (hence you feel a little lighter when accelerating downwards)
Therefore, the upward force of the elevator floor on the person must be less than 750N
Answer:
The refraction of light at the surface of water makes ponds and swimming pools appear shallower than they really are. A 1m deep pond would only appear to be 0.75 m deep when viewed from directly above. When light emerges from glass or water into air it speeds up again.
Explanation:
F - False.
The nucleus of an atom is positively charge.
