Hello!
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When objects are heated, their molecules tend to vibrate fast. As they vibrate, the space between each atom increases. This keeps on happening, and the object expands until it has cooled down.
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Hope this helps! :)
<u>Answer:</u> 0.774 g/cm^3
<u>Explanation:</u>
Density is measured in g/cm^3
480g / 620cm^3 = 0.774 g/cm^3
Does this help? Sorry if not.
Since, F = k . ∆x
Therefore, k = F / ∆x = 250 / 0.2 = 1250 N/m
(ps: convert 20 cm into 0.2 m)
The frequency of a wave becomes higher due to the object moving at a fast pace coming towards you with shorter wavelengths (depending on the speed) aka the Doppler Effect.
Hope this helps
