3) a stretched rubber band
Answer: relative motion between observer and the sound source.
Explanation: The Doppler effect states that when there is a relative motion between an observer and a sound source the frequency of sound perceived by the observer is different in frequency from the original from the source.
The mathematical back up for this claim is given below.
f' = (v+v') /(v-vs) × f
Where f' = observed frequency
v = speed of sound in air
v' = velocity of observer
vs = velocity of source
f = frequency of sound source.
From the formulae, it can be seen that a change in the value of the velocity of observer (v') and source (vs) produces different value of observed frequency (f').
Note, frequency of sound (f) is a constant.
Answer:
it's all around you and it can't be destroyed
The prongs on the plug and the wire inside<span> the </span>cord<span> are </span>metal<span> but they are </span>surrounded<span> by plastic or rubber insulation so you do not get shocked when you touch the </span>cord
Answer:
An indirect measurement of the speed of molecules is temperature
