## Crave the Wave B

John Richardsim
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### Crave the Wave B

Okay, let's get the Question Marathons populated (starting here).

What is an oscillation? How is an oscillation related to a wave?
Si Quaeris Peninsulam Amoenam Circumspice

ampy1234567
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### Re: Crave the Wave B

`An oscillation is a regular periodic motion. Oscillations are related to waves in that waves are a type of oscillations.`
Hm not sure too sure about second part
Mounds View High School, 10th grade

2016 Nationals: Dynamic (2), Disease (6), Crave (8), Fossils (22)
2017 Nationals: Disease (1), Dynamic (2), Optics (5)

John Richardsim
Wiki Moderator
Posts: 730
Joined: February 26th, 2014, 10:54 am
State: MI
Location: Robinson Twp.

### Re: Crave the Wave B

`An oscillation is a regular periodic motion. Oscillations are related to waves in that waves are a type of oscillations.`
Hm not sure too sure about second part
Yeah, I'll accept it. Your turn!
Si Quaeris Peninsulam Amoenam Circumspice

ampy1234567
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Posts: 38
Joined: March 31st, 2015, 6:11 pm
Division: C
State: MN

### Re: Crave the Wave B

`Say that galaxy A is actually blue, but appears red from planet B. If planet B is moving at a rate of 0.2c southward and galaxy A is moving at a rate of k*c northward, find k. Assume that the wavelengths of red and blue are 750 and 450 nm respectively, and ignore any possible effects of relativity.`
Mounds View High School, 10th grade

2016 Nationals: Dynamic (2), Disease (6), Crave (8), Fossils (22)
2017 Nationals: Disease (1), Dynamic (2), Optics (5)

Moderator
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Joined: December 6th, 2013, 1:56 pm
State: TX
Location: Austin, Texas

### Re: Crave the Wave B

`Say that galaxy A is actually blue, but appears red from planet B. If planet B is moving at a rate of 0.2c southward and galaxy A is moving at a rate of k*c northward, find k. Assume that the wavelengths of red and blue are 750 and 450 nm respectively, and ignore any possible effects of relativity.`
I thought I did this question but it looks like I forgot to submit it or something :/

Anyways, here's what I got:
`[b] k = 1/3[/b]. Work is here: http://imgur.com/JDUcEoF I got different answers doing it different ways, so it could be wrong T_T`
University of Texas at Austin '22
Seven Lakes High School '18
Beckendorff Junior High '14

ampy1234567
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Posts: 38
Joined: March 31st, 2015, 6:11 pm
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State: MN

### Re: Crave the Wave B

Yeah that's right
I had the same work as you BTW
Mounds View High School, 10th grade

2016 Nationals: Dynamic (2), Disease (6), Crave (8), Fossils (22)
2017 Nationals: Disease (1), Dynamic (2), Optics (5)

Moderator
Posts: 473
Joined: December 6th, 2013, 1:56 pm
State: TX
Location: Austin, Texas

### Re: Crave the Wave B

Yeah that's right
I had the same work as you BTW
When light passes through a different medium and slows down or speeds up, does the frequency or the wavelength change? Why?
University of Texas at Austin '22
Seven Lakes High School '18
Beckendorff Junior High '14

ampy1234567
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Posts: 38
Joined: March 31st, 2015, 6:11 pm
Division: C
State: MN

### Re: Crave the Wave B

`The wavelength changes. This is because the wave equation, which is (lamba)*f=speed, shows that a change in speed will cause changes in the frequency and/or the wavelength. Since the frequency remains constant (otherwise you would probably have a large "pile-up" of waves near the interface), wavelength therefore must change.`
Mounds View High School, 10th grade

2016 Nationals: Dynamic (2), Disease (6), Crave (8), Fossils (22)
2017 Nationals: Disease (1), Dynamic (2), Optics (5)

amydata123
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### Re: Crave the Wave B

no one has done a question for a while, so.........

8. As observed from the Earth, the light from a star is shifted
toward lower frequencies. This is an indication that the
distance between the Earth and the star is
(1) decreasing (3) constant
(2) increasing
"The road to success comes through hard work, determination, and sacrifice"
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ampy1234567
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Posts: 38
Joined: March 31st, 2015, 6:11 pm
Division: C
State: MN

### Re: Crave the Wave B

`2: Increasing`
Mounds View High School, 10th grade

2016 Nationals: Dynamic (2), Disease (6), Crave (8), Fossils (22)
2017 Nationals: Disease (1), Dynamic (2), Optics (5)