Answer:
Force = 125 [N]
Explanation:
In the attached image we can see a sketch of the lever system.
And if we make a sum of moments at the point O equal to zero (0).
In the equation showed in the image, we can determinate the force that we need
Boxers attempt to move with an opponent's punch when it is thrown. In other words, a boxer moves in the same direction as their
2 answers:
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Answer:
a) f' = 432 Hz
b) I = 8.12*10^-4 W/m^2
Explanation:
a) To calculate the frequency of sound waves that car receives, you take into account the Doppler effect. In this case (observer moves away of the source) you have the following formula:
(1)
where
f: frequency of the source = ?
v: speed of sound = 343 m/s
vo: speed of the observer = 40.0 m/s
vs: speed of the source = 0 m/s (stationary)
You replace the values of all parameters in the equation (1):
To calculate f' you first calculate the frequency of the sound wave, by using the following formula:
v: speed of sound
λ: wavelength = 0.700 m
Next, you replace the values of all parameters in the equation (1):
hence, the frequency perceived by the car is 432 Hz
b) To calculate the power of the sound wave, when the car is 70.0 maway from the speaker, you use the following formula:
P: power of the source = 50.0 W
r: distance to the source = 70.0 m
hence, the intensity is 8.12*10^⁻4 W/m^2