D. Only B and C
Medium and High levels can be harmful. But low even levels aren't good either.
Answer:
Explanation:
The water moving into the high tide areas has moved out of the low tide areas. Water is incompressible.
speed of sound wave depends on elasticity of medium and density of medium
it is given by formula

now if wave travel through solid then its speed is maximum while if it travel from gas then its speed is minimum
so initially its speed is given as 4000 m/s and suddenly decrease to 1500 m/s
so here we can say that its medium will change from solid to liquid
<em>so sound will encounter with water </em>
Answer:
As a freely falling object picks up downward speed. What happens to the power supplied by the gravitational force? Does it increase, decrease or stay the same? The power will increase because (Power=work/time; work=f(d); and F x d/t; FV).
Explanation: