Answer:
Explanation:
We shall apply Doppler's effect to solve the problem .
Formula for apparent frequency for a source of sound approaching an observer is as follows .
f₁ = f₀ V / (V - v )
where f₁ and f₀ are apparent and real frequency of source , V and v is velocity of sound and velocity of approaching source respectively .
Putting the given values and knowing that speed of sound is 340 m /s
f₁ =346x 340 / (340 - 39.6 )
f₁ = 391.6 Hz
In case of receding train , the formula is
f₂ = f₀ V / (V + v )
Putting the values
f₂ = 346x 340 / (340 + 39.6 )
= 309.9 Hz
Change in frequency = 391.6 - 309.9
= 81.7 Hz .
The moon's orbital plane is different from that of the earth's orbit around the sun due to which lunar and solar eclipses do not occur every month.
<h3 /><h3>What is a solar eclipse?</h3>
When the moon passes in front of Earth and the sun, it creates a solar eclipse and casts a shadow across the globe.
Only during the new moon phase, when the moon travels squarely between the sun and Earth and casts shadows on its surface, can a solar eclipse occur.
Due to the moon's orbit being five degrees off-center from Earth's orbit around the Sun, lunar eclipses do not happen every month and the Moon often passes above or below the shadow.
Lunar eclipses would happen every month if there were no tilt. Eclipses of the sun and the moon happen equally often.
Hence lunar and solar eclipses aren't coming every month.
To learn more about the solar eclipse refer;
brainly.com/question/17749647
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From the Hooke's law , the extension force of an elastic material is directly proportional to the extension.
That is, F = k e, where F is the force , k is the constant and e is the extension
F = 10 × 10 = 100 N
e = 1mm or 0.001 m
Hence, k = F/e
= 100 N/ 0.001
= 100000 N/m or 100 N/mm
