A) Transmitted through the medium
<span>A typical mirror in a person's house would be an
example of a/an plane mirror. Lenses and mirrors are different. Lenses is a
transparent tool containing two curved surfaces used to refract images – either
converge or diverge. Mirrors on the other
hand, show what the real image is without distortion.</span>
Answer:
Approximately .
Explanation:
Let denote the distance between the hikers and the mountain.
The sound wave from the hikers need to travel a distance of to reach the mountain. The echo comes back at the hikers almost immediately after that and would need to travel the same distance, , to reach the hikers.
Hence, the between the shout and the echo is the time it takes for sound to travel a distance of - twice the distance between the hikers and the mountain.
Distance that sound travels in :
.
The distance between the hikers and the mountains would be:
.
Answer:
Q = 1128.6 [kW] - kilowatts
Explanation:
To calculate the amount of energy required, the following expression should be used:
Q = 15*4.18*(38-20)
Q = 1128.6 [kW]
A 135-dB is 60-dB louder that 75-dB.
The question says "how much louder" so for these kinds of questions you subtract.
good luck!