Winston stands on the edge of a building's flat roof, 12 m above the ground, and throws a 147.0-g baseball straight down. the ba
ll hits the ground at a speed of 18 m/s. what was the initial speed of the ball?
1 answer:
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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
Answer:
the answer is C i didnt mean to put b lol
Explanation:
Explanation:
Let x = distance of from the fulcrum and let's assume that the counterclockwise direction is positive. In order to attain equilibrium, the net torque
about the fulcrum is zero:
Solving for <em>x</em>,