Answer:
Sound wave is a longitudinal wave that propagates in a medium
Explanation:
<em>Part A:</em> (C) Sound wave is propagation of pressure fluctuations in a medium.
<em>Part B: </em>(C) Pressure fluctuations travel along the direction of propagation of the sound wave.
<em>Part C: </em>(A) Yes air play a role in the propagation of the human voice from one end of the lecture hall to the other.
Your list of choices is a very short list, and doesn't include any
correct explanation.
The mass of an atom is roughly the number of protons AND neutrons
in its nucleus, but the element only depends on how many protons are there.
Different atoms of the same element may have different numbers of
neutrons, so their masses are different. But they're the same element,
because they all have the same number of protons.
The correct answer is A. Acid rain forms from human activities and lowers the pH of rainwater below 7
Explanation:
The term "acid rain" is used to refer to rainwater with a low pH or a high acidity, this includes rainwater with a pH below 7 (solutions with a pH under 7 are acidic). In terms of formation, acid rain is mainly the result of human activities such as factories or cars that release pollutants into the atmosphere including nitric and sulfuric acids and these alter the natural pH of rain and makes it more acidic. Additionally, acid rain has negative consequences such as the death of fishes and other organisms in lakes, rivers, etc. because the acidity is toxic to many organisms. Thus, acid rain is the result of human activities and it lowers the pH of rain (Option A).
First, let's express the movement of Car A and B in terms of their position over time (relative to car B)
For car A: y=20x-200 Car A moves 20 meters every second x, and starts 200 meters behind car B
For Car B: y= 15x Car B moves 15 meters every second and starts at our basis point
Set the two equations equal to one another to find the time x at which they meet:
20x - 200 = 15x
200 = 5x
x= 40
At time x=40 seconds, the cars meet. How far will Car A have traveled at this time?
Car A moves 20 meters every second:
20 x 40 = 800 meters
It's a multiple of 5 because you can't multiply anything by 2 and get 25
