# HELP needed on quick question - physicsWatch

#1
https://pmt.physicsandmathstutor.com...Waves%20QP.pdf

Q2A why is the answer 110Hz
Do not get octaves bit.
I looked at the textbook , cant seem to find a mention of octaves, can someone help me on this
0
2 months ago
#2
(Original post by Batman2k1)
https://pmt.physicsandmathstutor.com...Waves%20QP.pdf

Q2A why is the answer 110Hz
Do not get octaves bit.
I looked at the textbook , cant seem to find a mention of octaves, can someone help me on this
The following 2 links may help:
https://newt.phys.unsw.edu.au/jw/strings.html
https://newt.phys.unsw.edu.au/music/...itarintro.html
0
#3
I looked at the links, and what i can gather is...
scale position touched
fraction of string length
harmonic number
interval above open string

is the following in order

double octave 1/4 4 double octave

so if the q says usually instrument has 440Hz, but this instrument is in 1st harmonic fq but 2 octaves down,

But if its in 1st harmonic, and double octave = 4 harmonic number = 440Hz simple maths and divide by 4 = 110Hz

If my understanding is correct, it depends where you pluck the string scale touched, that produces an octave.
Think octave is an interval of some kind - very wordy text.
Is there anything to add on here? - thanks for showing me a source.

besides this, i am confused by a thing that is with a progressive wave:
in progressive waves, all points have the same amplitude (in turn), - unsure
in stationary waves, they do not - i get this nodes and antinodes

0
#4
another thing that bugged me was

https://pmt.physicsandmathstutor.com...Waves%20QP.pdf

Q3B and C is what i need help with - it is waves topic

MS here:
https://pmt.physicsandmathstutor.com...Waves%20MS.pdf

3b) half wavelength = 0.21m - got it.
but i dont understand 2(d2 - d1) = 2

3c) q just wants 2 know how 2 measure speed of sound from instrument device of some sorts

ms: Continue to move tube until tube is at greatest distance or repeat readings for decreasing
distance back to starting point.

confused here
0
2 months ago
#5
(Original post by Batman2k1)
another thing that bugged me was

https://pmt.physicsandmathstutor.com...Waves%20QP.pdf

Q3B and C is what i need help with - it is waves topic

MS here:
https://pmt.physicsandmathstutor.com...Waves%20MS.pdf

3b) half wavelength = 0.21m - got it.
but i dont understand 2(d2 - d1) = 2

3c) q just wants 2 know how 2 measure speed of sound from instrument device of some sorts

ms: Continue to move tube until tube is at greatest distance or repeat readings for decreasing
distance back to starting point.

confused here
The links to the questions seem to be broken.
0
#6
/A-level/Topic-Qs/AQA/03-Waves/Set-M/Superposition%20&%20Stationary%2 0Waves%20QP.pdf

MS:

Topic-Qs/AQA/03-Waves/Set-M/Superposition%20&%20Stationary%2 0Waves%20MS.pdf

(Original post by Eimmanuel)
The links to the questions seem to be broken.
oh damn it can now. by the way i appreciate your support on my understandings of physics.
Last edited by Batman2k1; 2 months ago
0
2 months ago
#7
(Original post by Batman2k1)
....
besides this, i am confused by a thing that is with a progressive wave:
in progressive waves, all points have the same amplitude (in turn), - unsure
in stationary waves, they do not - i get this nodes and antinodes
Transverse progressive wave
http://physics.bu.edu/~duffy/HTML5/wave.html

Transverse stationary wave
http://physics.bu.edu/~duffy/HTML5/t...ding_wave.html
You can press on the n = 1, n = 2, etc to look at the various amplitude at different positions.

In a progressive wave, energy is transported outward from the source and “it would affect all the particles evenly”, so all the particles would have the same amplitude.
0
2 months ago
#8
(Original post by Batman2k1)
...
3b) half wavelength = 0.21m - got it.
but i dont understand 2(d2 - d1) = 2
...

The “2” is to account for when d2 increases by x m, the movable tube increases the length by 2x: upper horizontal section increases by x m and lower horizontal section increases by x m.
0
2 months ago
#9
(Original post by Batman2k1)
...
3c) q just wants 2 know how 2 measure speed of sound from instrument device of some sorts

ms: Continue to move tube until tube is at greatest distance or repeat readings for decreasing
distance back to starting point.

confused here
There is a limit that the movable tube can extend.
I thought it is “obvious” that you need to repeat the experiment to ensure the “reproducibility” of your experimental result.
0
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