A spring has k = 88 N/m. Use a graph to determine the work needed to stretch it from x = 3.6 cm to x = 5.6 cm, where x is the displacement from its unstretched length.

3 answers

  1. You don't really need to draw a graph to figure that out. We can't draw them for you here, anyway. You will have to convert the 3.6 cm to 0.036 m and the 5.6 cm to 0.056 m.

    The answer is k[(.056)^2 - (.036)^2]
    If you used a graph to do it, you should plot the force kx vs x and measure tha area under the curve from x = 0.036 to x = 0.056. You should get the same answer, since the area is a trapezoid with width 0.020 and average height 0.046.

  2. but when you did this.... k[(.056)^2 - (.036)^2]

    k = 88 right?

    88(.056^2 - .036^2)

    then the answer would be .16192? it said that its incorrect. im alittle confused?

  3. It's because, you the equation is


    So you change the cm to meters, and then you subtract, getting (.02) then you get (.02)^2, cuz u have to square it,

    Then you * by K which is 88, and then divide by 2. That gives you the SPE, (spring potential energy)

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