When a car approaches you, the sound waves that reach you have a shorter wavelength and a higher frequency. You hear a sound with a higher pitch. When the car moves away from you, the sound waves that reach you have a longer wavelength and lower frequency.
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An approaching source moves closer during period of the sound wave so the effective wavelength is shortened, giving a higher pitch since the velocity of the wave is unchanged. Similarly the pitch of a receding sound source will be lowered.
The Doppler effect is an effect observed in light and sound waves as they move toward or away from an observer. One simple example of the Doppler effect is the sound of an automobile horn. Picture a person standing on a street corner. A car approaches, blowing its horn.
Comparing two waves of the same wavelength, a higher frequency is associated with faster movement. Comparing two waves of different wavelengths, a higher frequency doesn't always indicate faster movement, although it can. Waves of different wavelengths can have the same frequency.
The pitch of a sound is our ear's response to the frequency of sound. Whereas loudness depends on the energy of the wave. ... The pitch of a sound depends on the frequency while loudness of a sound depends on the amplitude of sound waves.
Total distance = 36500 m
The average velocity = 19.73 m/s
<h3>Further explanation</h3>
Given
vo=initial velocity=0(from rest)
a=acceleration= 1 m/s²
t₁ = 20 s
t₂ = 0.5 hr = 1800 s
t₃= 30 s
Required
Total distance
Solution
State 1 : acceleration


State 2 : constant speed

State 3 : deceleration


Total distance : state 1+ state 2+state 3

the average velocity = total distance : total time

The temperature of the plasma will increase as current is passed through it.
<h3>Meaning of Current and temperature</h3>
Current can be defined as a flow of charged particles through a medium and the particles includes: electrons or ions.
Temperature is the degree of hotness or coldness experienced by a material.
The more current passes through the plasma the more energy is induced making the particles to move faster which in turns causes temperature to increase and reducing the resistance of the plasma.
In conclusion, The current causes temperature to increase and this reduces the resistance.
Learn more about current: brainly.com/question/1100341
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Answer:
The minimum thickness = 83.92 nm
Explanation:
The relation between the wavelength in a particular medium and refractive index 
where ;
= wavelength of the light in vacuum
n = refractive index of medium with respect to vacuum
For one phase change :

Replacing 1.43 for n and 480 nm for λ; we have:

t = 83.92 nm
Thus; the minimum thickness = 83.92 nm
Answer:
increase
decrease
Explanation:
using formula
Vt=mg/6πηr
so if m increases V increases
r is the denominator so if r increases V decreases