just go buy some new springs. Its some of the best money you spend. Or you can hire an engineer and he can tell you all about ricing your car at 120 an hour. I'll be invoicing all of you for the time I spent on this thread. Oh, and good job on the AP exam. We are all very proud of you... my proudness accelerates at -9.8m/sec/sec

 

well if you got a 5 out of 100 then that explains it. I knew this post was going to get out of hand, it should probably be archived with a new title of "Cutting coils Does increase your Spring Rate"

 

Thanks trochoid, I wrote that down so, I can add it to my future project list. I am just trying to take it one step at a time. But if I see a good deal on any of my future projects then I buy whatever items I have listed on my book. That is why I ask all this questions just to make sure I don't ask about it later.

 

DriftFB seems to have gone missing.

 

no, actually, all of you are wrong, cutting coils decreases intelligence. The evidence to prove this is here in the thread.

Oh, and I'll match your 5 on the AP physics exam with mine, and a simple example as proof:

Two springs in series, each is the same spring rate K (say 200 lbs/in), each is L long (oh... 5 inches)

the equivalent rate for springs is given by the following equation:
1/Keq = 1/K1 + 1/K2

This can be derived from the fact that if the springs are in series and do a force analysis diagram, if there is a 400 lb force acting on the top of spring 1, there needs to be a 400 lb force acting on its bottom, otherwise it would fly away (if the forces werent balanced). This 400 lb force is provided by spring 2, sitting underneath, which is then supported with another 400 lb force from the ground underneath. So each spring sees 400 lbs with one 400 lb weight on top

___________
|.....|...............|
|....\/..400 lbs.|
|___________|
........| - - - - - - - -
.......<............|
.........> Spring 1
.......<............|
........| - - - - - - - -
.......<............|
.........> Spring 2
.......<............|
____|______|___
......./\..Ground
........|...400 lbs

(EDIT - sorry for the periods, they were needed to space the picture properly to prevent reformatting)

now, each spring will compress 2 inches (200 lbs/in / 400 lbs), for a total of 4 inches Thus, the equivalent spring rate for these two springs in their current arrangement is 400 lbs/4 inches = 100 lbs per inch. See where I'm going?

If you "cut" this equivalent spring in half (taking just spring 1 or 2), these have a spring rate of 200 lbs per inch as stated in the problem definition. Thus, cutting the spring in half doubles the spring rate (without changing actual spring properties besides length and the number of active coils)

I think its time for some people to re-take hs physics

 

Damn nice toplessFC3Sman, Good write up. hehe...

 

It got to the point where I didn't think I was reading the calculator right, so made that post asking for clarification, and now I'm just watching the people with better info argue. I don't want to add in anything because right now I feel like it might be mis-information.

And I didn't get on yesterday.