Think about how each of noise, heat, visible light, radiation and atmospheric shock waves travel. Which ones require air particles to travel?
A vacuum has no air particles within it, it is completely empty.
Therefore, any of the above that requiring particles to travel will not be able to cross it and the observer will not experience it.
Answer: The answer: The car is moving away from you.
Both A and C are true as Car can be moving in line away from you or has component of velocity in opposite direction.
Explanation:The decrease in the frequency of the sound is the result of Doppler's effect. A/c to Doppler's effect the frequency of received sound of source is changed if it is moving relative to the receiver, i.e. the distance between them is changing due to motion.
The general formula of Doppler's Effect is attached as the picture.
In this formula v_D is the velocity of Detector i.e the receiver relative to wind. While v_s is the velocity of source relative to wind and v is the velocity of sound.
The Doppler's effect is not effected by the velocity of wind as the wind itself could not change the distance between the two objects i.e. you and the car. Wind velocity can change the speed of sound and its wavelength but the change does not effect the frequency.
Hence if we assume the car to be moving with velocity v_c and you are stationary

hence the frequency is reduced.
Explanation:
Given that,
Frequency in the string, f = 110 Hz
Tension, T = 602 N
Tension, T' = 564 N
We know that frequency in a string is given by :
, T is the tension in the string
i.e.
, f' is the another frequency


f' =106.47 Hz
We need to find the beat frequency when the hammer strikes the two strings simultaneously. The difference in frequency is called its beat frequency as :



So, the beat frequency when the hammer strikes the two strings simultaneously is 3.53 beats per second.
Answer:
0 m/s cause they crashed so they can't move
Answer:
The electric field direction within a circuit is by definition the direction that positive test charges are pushed. Thus, these negatively charged electrons move in the direction opposite the electric field.
Explanation:
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