Answer:
In most materials, as heat energy is absorbed, the density decreases. IF a certain object is heated, it might appear bigger than usual because it expands as the molecules inside moves faster than usual. However the mass of it stays the same while the density decreases.
Frequency is defined as the number of repetitions of waves occurring in 1 second. The frequency heard by the man as the ambulance move toward him will be greater than 450 Hz.
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What is the frequency ?</h3>
Frequency is defined as the number of cycles completed in 1 second. Frequency is given by the formula as,

As the formula shows frequency is inversely proportional to the time that shows if the time is decreasing frequency will increase and vice versa.
In the above case, the ambulance is moving toward the men. So that the time to meet up is decreased that's why the frequency will be greater than the initial frequency from the siren.
Hence the frequency heard by the man as the ambulance move toward him will be greater than 450 Hz.
To learn more about frequency refer to the link ;
brainly.com/question/4393505
Answer:
in a transverse wave, The directions that energy and matter travel in are perpendicular to one another.
these waves are types of mechanical waves that doesn't require any material medium to transfer.
Answer:
answer is D.it will decrease
Answer:
B)
Explanation:
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