Answer:
20 hz - 20khz is the audible sound wave for humans
B, C, and D.
Solar energy is green energy, it wouldn't contribute to global warming. However some places of the world don't receive as much sunlight (the poles) and at night you don't receive as much sunlight either. Solar energy is also very expensive to farm.
Answer:
t = 12.8 s
Explanation:
As we know that the deepest point of the canyon is 800 m
so here we will have the displacement of the rock in the canyon is same as that of depth of the canyon
So here we will say



now we have


