the inside surfaces of the glass inside thermos bottles are coated with aluminum to prevent energy transfers by
2 answers:
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Answer:
velocity = 472 m/s
velocity = 52.4 m/s
Explanation:
given data
steady rate = 0.750 m³/s
diameter = 4.50 cm
solution
we use here flow rate formula that is
flow rate = Area × velocity .............1
0.750 = × (4.50×
)² × velocity
solve it we get
velocity = 472 m/s
and
when it 3 time diameter
put valuer in equation 1
0.750 = × 3 × (4.50×
)² × velocity
velocity = 52.4 m/s
Answer: The frequency heard will be f = 275.675Hz
Explanation: When an object emitting sound is moving, it occurs a phenomenon called Doppler shift or Doppler effect. What happens is that the sound gets higher when the moving object comes closer the observer and becomes lower after it passes, This change is due to the quantity of waves that passes through an area in an unit of time.
The formula to calculate the Doppler effect is as follows
f = () · f₀
f is the observed frequency;
c is the speed of sound;
Vs is velocity of the source;
f₀ is the emitted frequency of source;
Substituting and calculating,
f = · 300
f = 275.675 Hz
Thus, the frequency heard by the police officer is 275.675Hz.