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 .
Distance = velocity (or speed) x time
so, distance = 0.30 meters.min x 15 mins
distance = 4.5 meters
Answer:
7. 1ml = 20 drops
325ml = 6500
( 325 x 20 = 6500)
there are 6500 drops in a pepsi can
8. not sure sorry ; (
9. 1 mile per hour = 88 feet per minute
45 miles per hour = 3960 feet per minute
( 88 x 45 = 3960)
there are 3960 feet per minute in 45 miles per hour
When the metal wire in an incandescent lightbulb glows when the light is switched on and stops glowing when it is switched off, this is an example of resistance, which provides light and heat.
Answer: True
Explanation:
The phases occur because the sun lights different parts of the moon as the moon revolves around the earth
