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Nastasia [14]
3 years ago
8

An astronomer observes that the wavelength of light from a distant star is shifted toward the red part of the visible spectrum.

Which of the following is true? - The distance between the earth and the star is decreasing. - The distance between the earth and the star is remaining constant. - The distance between the earth and the star is increasing.
Physics
1 answer:
balandron [24]3 years ago
7 0

Answer:

The distance between the earth and the star is increasing.

Explanation:

When we observe an object and its electromagnetic radiation has been displaced to blue, it means that it is getting closer to us, causing the light waves it emits to get closer together and its wavelength to decrease towards blue, this is knowm as blueshift.

On the contrary, when an object is rapidly moving away from us, the light waves or electromagnetic radiation it emits have been stretched from their normal wavelength to a longer wavelength, towards the red part of the spectrum. This is known as redshift.

This phenomenon of changes in wavelength and frequency due to movement (whether the source approaches or moves away) is described by the Doppler effect.

So for this case because the light we perceive from the star has moved to the red part of the visible spectrum, we can conclude that it is moving away from the earth, and that the distance between the star and the earth is increasing.

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A hypothesis is _______.
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Answer:

A hypothesis is a basically a theory proposed to a subject or refrence to an act with limited evidences.

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A tennis player swings her 1000 g racket with a speed of 10 m/s. She hits a 60 g tennis ball that was approaching her at a speed
Mashutka [201]

(a)

consider the motion of the tennis ball. lets assume the velocity of the tennis ball going towards the racket as positive and velocity of tennis ball going away from the racket as negative.

m = mass of the tennis ball = 60 g = 0.060 kg

v₀ = initial velocity of the tennis ball before being hit by racket = 20 m/s

v = final velocity of the tennis ball after being hit by racket = - 39 m/s

ΔP = change in momentum of the ball

change in momentum of the ball is given as

ΔP = m (v - v₀)

inserting the above values

ΔP = (0.060) (- 39 - 20)

ΔP = - 3.54 kgm/s

hence , magnitude of change in momentum : 3.54 kgm/s

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3 years ago
There are three ways to give an object a static charge. They are friction, conduction and induction. Two pieces of cellophane ta
Novay_Z [31]

The tape is charged by friction and her hand has an induced opposite charge. They therefore attract.

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3 years ago
Read 2 more answers
A flutist assembles her flute in a room where the speed of sound is 342 m/s. When she plays the note A, it is in perfect tune wi
sertanlavr [38]

Answer:

5.15348 Beats/s

4.55 mm

Explanation:

v_1 = Velocity of sound = 342 m/s

v_2 = Velocity of sound = 346 m/s

f_1 = First frequency = 440 Hz

Frequency is given by

f_2=\frac{v_2}{2L_1}\\\Rightarrow f_2=\frac{346}{2\times 0.38863}\\\Rightarrow f_2=445.15348\ Hz

Beat frequency is given by

|f_1-f_2|=|440-445.15348|=5.15348\ Beats/s

Beat frequency is 5.15348 Hz

Wavelength is given by

\lambda_1=\frac{v_1}{f}\\\Rightarrow \lambda_1=\frac{342}{440}\\\Rightarrow \lambda_1=0.77727\ m

Relation between length of the flute and wavelength is

\lambda_1=2L_1\\\Rightarrow L_1=\frac{\lambda_1}{2}\\\Rightarrow L_1=\frac{0.77727}{2}\\\Rightarrow L_1=0.38863\ m

At v = 346 m/s

\lambda_2=\frac{v_2}{f}\\\Rightarrow \lambda_2=\frac{346}{440}\\\Rightarrow \lambda_1=0.78636\ m

L_2=\frac{\lambda_2}{2}\\\Rightarrow L_2=\frac{0.78636}{2}\\\Rightarrow L_2=0.39318\ m

Difference in length is

\Delta L=L_2-L_1\\\Rightarrow \Delta L=0.39318-0.38863\\\Rightarrow \Delta L=0.00455\ m=4.55\ mm

It extends to 4.55 mm

7 0
3 years ago
Which temperature scale has the highest value for the boiling point of water?
drek231 [11]

Answer: The correct answer is kelvin.

Explanation:

The expression for the conversion of degree Celsius to Kelvin is as follows:

K= 273 + degree Celsius

The expression for the conversion of degree Celsius to Fahrenheit is as follows:

F=(Degree Celsius\times \frac{9}{5})+ 32

The freezing point of water on Celsius degree is zero degree Celsius. The freezing point on kelvin scale is 273.15 K.

The boiling point of water on Celsius degree is 100 degree Celsius. The boiling point on kelvin scale is 373.15 K.  The boiling point on Fahrenheit scale is 373.15 K.

Therefore, Kelvin scale has the highest value for the boiling point of water.

6 0
3 years ago
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