A few months ago, I was making a firing canon that recoils, but there was limited space for the canon to recoil (it was on a ship). I knew how much force the canon produced when it fired, and the maximum distance the canon was allowed to recoil, so if I could find the spring constant of the shock part, I could make my canon without having try to find a nice spring-strength through trial and error. Finally after 4 months of procra- I mean investigating, I've found that the spring constant of the shock in SR2 is 100,000N/m.

That value is for shocks at spring-strength 1 (100%). For different strengths, the spring constant increases proportionally, so the formula is;

k = Spring-strength x 100,000
Where k is the spring constant, and 100,000 is the base multiplier.

The Investigation

I used 3 methods for the investigation. The first is by varying the force on the shock, the 2nd by varying the parameters of the shock (Strength, Thickness, and Size - Dampening would not affect the spring constant), and a 3rd informal method a mixture of the 1st two.


Dependent Variable: Mass (Strength, Thickness, Size in 2nd investigation)
Independent Variable: Extension
1. Design a ruler that is easy to use to measure length contractions. This is one I used; each segment is 0.1m, with a tile texture to split each segment in half. This gives an accuracy to 0.025m.

2. Add springs around the ruler, making sure the properties are kept constant, and recording the properties. Add different masses on the springs. Calibrate the springs so the top of the masses align with the top of the ruler, eliminating zero-error. Set dampening to 2.5 to reduce oscillation.

3. Make one of the springs 2.5 Strength, with a set mass. Do not change the spring properties or mass of this particular spring throughout the investigation. This will be the control spring, so if the extension of this spring is not what it is usually, you'll know something is wrong with the craft/parts.
4. Run the craft and measure the contraction of each mass. Make a table of mass and extension. You can use a ruler in real-life to measure to a better accuracy, however, make sure to reduce parallax error.

5. Perform the same experiment 1 or 2 more times if you want accuracy.
6. Perform the experiment with a constant mass but different spring property (one property at a time), and record on the table (record the spring property difference). Remember not to change the control spring. Also perform with the same method but different masses as well as spring-properties.

F = Force
k = Spring Constant
m = Mass
g = Gravity

7. Plot several graphs of either Extension against Mass, or Mass against Extension. Here I've plotted Extension against Mass. The gradient of mine is x/m, and in the form of y = mx + c, rearranging F = kx, we get k = m/x x g. So k = 1/gradient x 9.81, where the gradient is Extension divided by Mass.

The Spring Constant you should get should be around 100,000Nm^-¹


You may suffer from PTSD trying to get everything to behave. If at any point you feel stressed, stop the investigation at once and postpone the investigation.



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  • Profile image
    6,697 JamesV4

    Your like the perfect groupmate on research project (school)

    2.7 years ago
  • Profile image
    1,454 t4zcomz

    @zeropol Nono, you have it right. What I'm saying is that I don't understand why the scientific community says a ruler can't be more precise than its smallest scale, because to me, it should be that a ruler can't be more precise than half its smallest scale (because of what I explained below).

    And yes, parallax error would be big in my case. But that doesn't matter too much because I knew Jundroo would make the spring constant multiplier an easy number, like 100,000, rather than, say 99,298. So as long as my results revolved around an easy number, I could find the true value.

    +1 3.3 years ago
  • Profile image
    358 zeropol

    I may be wrong, but I suppose a ruler can't be more precise than its smaller scale. ( if you consider that "I draw somewhere in between" give it more precision, I'm fine with it, but I would not pretend this myself. )
    Anyway, I like the spirit of your post ^_^

    Edit : to clarify my affirmation : I think if I measure somewhere between 1.5 and 2, I have to say the measure is the nearest scale +- my ruler+pen margin of error. For your post, imprecision would be mainly related to the camera angle of view, depth of view and distance between the object to measure and the "ruler block", and your own appreciation of where the block/texture ends. Again I may be wrong, if someone read this and know I'm wrong feel free to correct me.

    3.3 years ago
  • Profile image
    1,454 t4zcomz

    @zeropol I was hoping someone would point that out, because I just can't see why the accuracy would be 0.5.
    If I measure a value to be between 1.5 and 2, shouldn't I put it as 1.75 +or- 0.25 (and therefore an accuracy of 0.25)?
    I was taught that it would be 1.5 +or- 0.5, but that would mean the value is between 1 and 2, when we know it's between 1.5 and 2. I don't understand it

    3.3 years ago
  • Profile image
    7,456 Hannah1212

    Useful information, also wow that experiment looks like a lot of work

    3.3 years ago
  • Profile image
    358 zeropol

    science !

    each segment is 0.1m, with a tile texture to split each segment is half. This gives an accuracy to 0.025m.

    ( isnt the accuracy 0.5 so ? )

    3.3 years ago
  • Profile image
    1,454 t4zcomz

    Don't mind me, this is just to improve my practicals skills.

    3.3 years ago


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