A stationary siren on a firehouse is blaring at 81Hz. Assume the speed of sound to be 343m/s. What is the frequency perceived by
1 answer:
For a stationary siren on a firehouse is blaring at 81Hz. Assume the speed of sound to be 343m/s, the frequency perceived is mathematically given as'
F=81.721Hz
<h3>What is the frequency perceived by a firefighter racing toward the station at 11km/h?</h3>Generally, the equation for the doppler effect is mathematically given as
Therefore
F=81(343+3.05556)/343
F=81.721Hz
In conclusion, the frequency is
F=81.721Hz
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The given question is incomplete. The complete question is as follows.
The block has a weight of 75 lb and rests on the floor for which = 0.4. The motor draws in the cable at a constant rate of 6 ft/sft/s. Neglect the mass of the cable and pulleys.
Determine the output of the motor at the instant .
Explanation:
We will consider that equilibrium condition in vertical direction is as follows.
N - W = 0
N = W
or, N = 75 lb
Again, equilibrium condition in the vertical direction is as follows.
= 0
=
= 30 lb
Now, the equilibrium equation in the horizontal direction is as follows.
or, T =
=
=
= 17.32 lb
Now, we will calculate the output power of the motor as follows.
P = Tv
=
=
= 0.189 hp
or, = 0.2 hp
Thus, we can conclude that output of the given motor is 0.2 hp.