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Determination of the spring constant of a jumping spring

  1. Dec 14, 2009 #1
    1. The problem statement, all variables and given/known data

    I am having some difficulty in this experiment in determining the spring constant. It involves measuring the height the spring figure bounces and each time adding extra weight and recording the differences in the height. I've recorded the data, plotted a graph of y(spring height) v x(1/m spring mass) and got the slope of the graph. The problem i am having is arranging the equation to find k, the spring constant. Somebody help!
    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Dec 14, 2009 #2


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    Hi, Tony, welcome to PF!
    (1) You are talking about a 'bouncing' spring? Do you add the weight slowly and measure how much it stretched from its original length, once it settles into its at rest position? If yes, plot the Force (objects weight) on the y axis and the spring displacement from its unstretched length on the x axis, and you should get more or less a straight line, the slope of which is 'k'. I am assuming the spring's mass is negligible, correct? What did you mean by " (I)plotted a graph of y(spring height) v x(1/m spring mass)" ?

    (2) Now if you are actually releasing the weight quickly and letting the spring bounce, that's another story. You'll get larger deflections that way.

    Am I understanding your question correctly?
  4. Dec 15, 2009 #3
    Hi, thanks for the fast reply!

    Sorry if im not that clear on the experiment. It involved a figure with a spring, when pressed after a few seconds it would bounce and the height of the bounce recorded. Then some blue tac would be added to the spring and the height of the bounce recorded again, obviously less each time as the spring gets heavier. This was done roughly ten times to get the points to plot a straight line graph, with y as the different heights and x as the different weights. Calculate the slope and then use the appropriate equation to find k, the spring constant.

    I have plotted the graph, calculated the slope but i dont know how to manipulate the equation to find the spring constant. I hope you can understand what im trying to say!
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