Respuesta :
v= 19.60 m/s (Speed before train slowing down)
v= 9.80 m/s Speed after train slowing down
Given:
- Train whistle,=280 Hz
- Sound of whistle,= 270 Hz
- Speed of sound= 343 m/s
Now,
→ 270= F×[tex]\frac{343}{343-v}[/tex]......equation 1
→ 280= F×[tex]\frac{343}{343-\frac{v}{2} }[/tex].....equation 2
After dividing "equation 1" by "equation 2", we get
→ [tex]\frac{280}{270} =\frac{343-\frac{v}{2} }{343-v}[/tex]
By applying cross-multiplication, we get
→ 1.0370(343-v) =343-[tex]\frac{v}{2}[/tex]
→ 353.39-1.030 v= 343-0.5 v
353.39-343 = 1.03 v-0.5 v
10.39 = 0.53 v
v= [tex]\frac{10.39}{0.53}[/tex]
v= 19.60 m/s (Speed before train slowing down)
hence,
Speed after train slowing down will be:
= [tex]\frac{v}{2}[/tex]
= [tex]\frac{19.60}{2}[/tex]
= 9.80 m/s
Thus the responses above are correct.
What is speed with example?
Speed is a way of measuring how quickly something is moving or being done, or something moving fast. An example of speed is a car being driven 45 miles per hour. An example of speed is someone cleaning a room in 10 minutes. An example of speed is how quickly a jaguar run
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