# Physics SpringsWatch

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Thread starter 5 years ago
#1
Hi there - wondering if i can get any help with the following spring questions... Im completely lost

2.a
two identical springs of length 250mm are suspended in parallel. a 40n weight is attached. The length of each spring is now 350mm.

i) calculate tension in each spring
ii) the extension of each spring
iii) spring constant of each spring

b - both springs are now suspended in series. Calculate.
i) tension in each spring
ii) extension of each spring
iii) spring constant of each spring

Thanks to anyone to can help (if u can help an explanation would be fantastic)
0
5 years ago
#2
(Original post by longsightdon)
Hi there - wondering if i can get any help with the following spring questions... Im completely lost

2.a
two identical springs of length 250mm are suspended in parallel. a 40n weight is attached. The length of each spring is now 350mm.

i) calculate tension in each spring
ii) the extension of each spring
iii) spring constant of each spring

b - both springs are now suspended in series. Calculate.
i) tension in each spring
ii) extension of each spring
iii) spring constant of each spring

Thanks to anyone to can help (if u can help an explanation would be fantastic)
What don't you understand?
For example.
Part a ii)
Are you telling us that if a spring is initially 250mm and stretches to 350mm you can't calculate the extension?

Tell us what you have done or can do so far and we will help with the rest.

A tip to get you started.
With two springs in parallel, they must, together, provide a force upwards (tension) equal to the weight being supported. Each spring has a tension equal to half the weight of the mass.
1
Thread starter 5 years ago
#3
(Original post by Stonebridge)
What don't you understand?
For example.
Part a ii)
Are you telling us that if a spring is initially 250mm and stretches to 350mm you can't calculate the extension?

Tell us what you have done or can do so far and we will help with the rest.

A tip to get you started.
With two springs in parallel, they must, together, provide a force upwards (tension) equal to the weight being supported. Each spring has a tension equal to half the weight of the mass.

I don't understand what tension is at all and I really don't know any thing about series or parallel springs. I can calculate the extension for aii but im struggling with everything else. Sorry if I sound really stupid
1
5 years ago
#4
(Original post by longsightdon)
I don't understand what tension is at all and I really don't know any thing about series or parallel springs. I can calculate the extension for aii but im struggling with everything else. Sorry if I sound really stupid
This makes me ask you what you have studied for this topic.
How can you be doing questions on extension of springs if you don't know what tension is? You must have done this in class.

Have you studied Hooke's Law?

This gives the relationship between extension and tension.
0
Thread starter 5 years ago
#5
(Original post by Stonebridge)
This makes me ask you what you have studied for this topic.
How can you be doing questions on extension of springs if you don't know what tension is? You must have done this in class.

Have you studied Hooke's Law?

This gives the relationship between extension and tension.
All we've done so far is done the equation and done an experiment on springs. My teacher expects us to do this sheet (even it seems she hasn't taught us some of the things on it)
0
5 years ago
#6
(Original post by longsightdon)
All we've done so far is done the equation and done an experiment on springs. My teacher expects us to do this sheet (even it seems she hasn't taught us some of the things on it)
Right, well let's look at the 1st question 1st.

2a.

You need to know that if the springs are "in parallel" all it means is they are side by side, hanging down, and together holding up the 40N weight. As the springs are identical, each one must be under 20N tension. This is because the 40N downwards force from the weight must be balanced by two 20N forces, one from each spring. This is just the basic idea of balanced forces. Forces in equilibrium.

You have the answer to part i) now. And ii) from the extension you say you can calculate from before.

If you have done "the equation" I assume that is Hookes Law.
This says T = ke
or
tension in spring = spring constant x extension

as you know tension and extension now you can find the spring constant, k.

Let us know what your answers are to the 3 parts of this question, then we can look at the 2nd question with the springs "in series". That is, end to end rather than side by side.
0
Thread starter 5 years ago
#7
2a
i) so the tension is 20N in each spring
ii) 100mm is the extensions
iii) 1/5 is the constant?
0
5 years ago
#8
(Original post by longsightdon)
2a
i) so the tension is 20N in each spring
ii) 100mm is the extensions
iii) 1/5 is the constant?

i and ii are ok

For 3 you need the tension in N (which is 20N) and the extension in metres.
100mm is 0.1m
to get the spring constant in Nm-1
So the answer is not quite as you've expressed it.

For part 2b

part iii is the same answer for spring constant of the individual springs as part aiii because it's the same springs. This seems like a silly question.

The difference in this calculation is that now the springs both have 40N tension as they are end to end.

Use the spring constant from the 1st question, plug it and the 40N tension into the formula, to get the extension of each spring. Be careful of the units.
0
2 years ago
#9
(Original post by longsightdon)
2a
i) so the tension is 20N in each spring
ii) 100mm is the extensions
iii) 1/5 is the constant?
How did you get 20N?
0
2 years ago
#10
(Original post by noumanahaq)
How did you get 20N?
????????

A force of 40N is shared between two identical springs.

This thread is also over three years old.
0
2 years ago
#11
(Original post by uberteknik)
????????

A force of 40N is shared between two identical springs.

This thread is also over three years old.
oh! i didnt notice that and i just started doing a level physics and i was overthinking this question. thanks anyways.
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