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3 years ago

How can astrophysicists tell whether a star is receding from or approaching earth?

Physics

1 answer:

MrMuchimi3 years ago

3 0

Answer:

Doppler shift of the starlight

Explanation:

To predict the movement of a star, we compare the spectra of elements found in star (H, He Na etc.), first spectra which are obtained from star and second spectra from laboratory. If spectral lines of the spectra obtained from star, are shifting towards red end (called red shift) then star is going away from earth and if shifting is towards blue (called blue shift), then star is approaching the earth. This is Doppler's shift.

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Diego is trying to lift a piano to the second floor of his house. Diego uses a pulley system and gives a big lift to the piano.T

andreyandreev [35.5K]

Answer:he to

Explanation:

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2 years ago

To view an interactive solution to a problem that is similar to this one, select Interactive Solution 7.24. A 0.0129-kg bullet i

ipn [44]

Answer:

t=0.42s

Explanation:

Here you have an inelastic collision. By the conservation of the momentum you have:

$m_1v_1+m_2v_2=(m_1+m_2)v$

m1: mass of the bullet

m2: wooden block mass

v1: velocity of the bullet

v2: velocity of the wooden block

v: velocity of bullet and wooden block after the collision.

By noticing that after the collision, both objects reach the same height from where the wooden block was dropped, you can assume that v is equal to the negative of v2. In other words:

$m_1(-v_1)+m_2v_2=(m1+m2)(-v2)$

Where you assumed that the negative direction is upward. By replacing and doing v2 the subject of the formula you get:

$-(0.0129kg)(767m/s)+(1.17kg)v_2=(1.1829kg)(-v_2)\\\\v_2=4.20m/s$

Now, with this information you can use the equation for the final speed of an accelerated motion and doing t the subject of the formula. IN other words:

$v_2=v_o+gt\\\\t=\frac{v_2-v_o}{g}=\frac{4.2m/s-0m/s}{9.8m/s^2}=0.42s$

hence, the time is t=0.42 s

4 0

3 years ago

What unit is used to measure the period of a wave?

mixer [17]

Answer:

D. Meters/Seconds

Explanation:

The time period of a wave is measured in seconds.

A typical wave involves both time and distance. Consider a sound wave, which is basically a periodic modulation of the local air pressure. We "hear" the sound because our ears respond to the variations of pressure.

The most common metric of a sound wave is frequency. This is the rate at which the change in pressure occurs, and is measured in cycles per second, formally known as "hertz". The period is the inverse of frequency andl has the units of seconds per cycle, commonly stated simply as seconds.

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2 years ago

Volume is a measurement of the height of the wave known as what? <br><br><br> this is science

Cerrena [4.2K]

I’m gonna have to say “Ocean waves” as the answer

6 0

3 years ago

Read 2 more answers

Does anyone know any sites that you can use for physics for like homework

UNO [17]

Answer:

the app your on now is great and can ask anything

5 0

2 years ago