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Tema [17]
3 years ago
14

A bird is flying directly toward a stationary bird-watcher and emits a frequency of 1420 Hz. The bird-watcher, however, hears a

frequency of 1456 Hz. What is the speed of the bird, expressed as a percentage of the speed of sound
Physics
1 answer:
kogti [31]3 years ago
7 0

Answer:

2.47 %

Explanation:

We are given;

Frequency emitted by source(bird); f_s = 1420 Hz

Frequency heard by observer; f_o = 1456 Hz

From doppler shift frequency, we know that;

f_o = f_s [c/(c - c_s)]

Where c_s is speed of source which is the bird and c is speed of sound.

Thus;

Rearranging the equation, we have;

f_s/f_o = (c - c_s)/c

f_s/f_o = 1 - (c_s/c)

Plugging in the relevant values to get ;

1420/1456 = 1 - (c_s/c)

0.9753 = 1 - (c_s/c)

1 - 0.9753 = (c_s/c)

(c_s/c) = 0.0247

Since we want it expressed im percentage,

Thus, (c_s/c) % = 0.0247 x 100 = 2.47 %

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What would be the mass of an object that has a force of 88N and an acceleration of 12 m/s2?
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7.33 kg

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0.5083\ \mu m

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Answer:

 ∑ τ =0,  L₀ = L_{f}

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- Another possibility is that the arms have stuck to the body, in this case the person's muscles perform the force, this force is horizontal and the displacement is the horizontal of the center of mass of the arms from the extended position to the contracted

 

In these movements the torque of the external force is equal for each arm, but in the opposite direction, so they are canceled where a net torque of zero, this causes the angular momentum to be preserved, which changes is the moment of inertia of the system and therefore you must also change the angular velocity to keep your product constant

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                L₀ = L_{f}

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