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# M3: Another Hooke's law question watch

1. I've been having some problems with Hooke's law questions and those that relate to simple harmonic motion. I seem to be having problems when you have a particle connected in the middle of two strings that are attached to either side.

For example, question 3 on this paper. I started off part (i) by working out that:

In string PB, T = ke so T = 35 (x - 3.2) = 35x - 112.
But what would the extension be in the other string? I tried using that extension as (6.5 - (x - 3.2)) but for some reason it didn't work. Could someone explain this to me?

Could someone also explain how to find extensions in connected strings in general?
2. (Original post by OL1V3R)
I've been having some problems with Hooke's law questions and those that relate to simple harmonic motion. I seem to be having problems when you have a particle connected in the middle of two strings that are attached to either side.

For example, question 3 on this paper. I started off part (i) by working out that:

In string PB, T = ke so T = 35 (x - 3.2) = 35x - 112.
But what would the extension be in the other string? I tried using that extension as (6.5 - (x - 3.2)) but for some reason it didn't work. Could someone explain this to me?

Could someone also explain how to find extensions in connected strings in general?
Im not really sure what I got is right..
I got 6.5-(x+1.8)

edit:I didn't see the ms below.
The extension in the string is done by (6.5-x) which gives you QB and in QB the natural length is 1.8 so the total extension is
(6.5-x)-1.8 =6.5-(x+1.8)
3. Don't worry, I now understand it!

Thanks anyway!

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