Answer:
Explanation:
The change of frecuency of sound due to the movement of the source is colled Doppler Effect.
As James (the source) is running toward the wall, the frecuency reaching the wall (so the eco sound) will be higher than the source. In this case the frecuency at the wall will be:
where is the speed of source, 2 m/s
and is the speed of sound, given that we have wind movind the air in the opposite direction respect to the wall, the speed of sound would be:
Replacing the values:
Now the wall becames the new source, and James (the observer is aproaching the source), for an observer aproaching the source the new frecuency will be:
Now the waves are traveling in the direction of wind, so the velocity of sound will be:
Replacing:
Answer:
a) the frequency of the wave is 0.2 Hz
b) the speed of the wave 4 m/s
Explanation:
Given that;
time period = to complete one cycle t = 5 sec
frequency f = 1/t
frequency f = 1 / 5sec
f = 0.2 Hz
Therefore the frequency of the wave is 0.2 Hz
b)
speed of wave V = λf
given that our wavelength is 20.0 m
we substitute
speed of wave V = 20.0 × 0.2
speed of wave V = 4 m/s
Therefore, the speed of the wave 4 m/s
Generally speaking, negative ions increase the flow of oxygen to the brain resulting in higher alertness, decreased drowsiness, and more mental energy.
Answer:
A) conductors
Explanation:
A conductor can be defined as any material or object that allows the free flow of current or electrons (charge) in one or more directions in an electrical circuit. Some examples of a conductor are metals, tungsten, copper, aluminum, iron, graphite, etc.
Basically, the main purpose of a conductor in physics is to provide a low-resistance path between electrical circuits or components. This low-resistance path is to ensure that the electrical components allows the free flow of electrons and thus, enabling charge transfer.
Hence, the electrons in conductors move about more freely than the electrons in insulators which is why this type of material can be used to create electric circuits because it would significantly provide a low-resistance path between the electric circuits.
Answer:
(a) Q = 142.67 W
(b) Basal Metabolic Rate = 178.33 W
Explanation:
(a)
We can find the heat radiated by the person by using Stefan-Boltzman's law:
where,
Q = heat radiated per second = ?
σ = Stefan-Boltzman Constant = 5.6703 x 10⁻⁸ W/m².k⁴
A = Surface Area = 2 m²
T = Temperature of Skin = 30° C + 273 = 303 k
Ts = Temperature of room = 18° C +273 = 291 k
Therefore,
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<u>Q = 142.67 W</u>
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(b)
Since the heat calculated in part (a) is 80 percent of basal metabolic rate. Therefore,
<u>Basal Metabolic Rate = 178.33 W</u>