vinnyzwrx
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Homework Statement
At a certain point, when a spring is stretched near its elastic limit, the spring force satisfies the equation
F = −α x + β x3 , where α = 12 N/m and β = 890 N/m3 .
Calculate the work done by the spring when it is stretched from its equilibrium position to 0.15 m past its equilibrium.
Answer in units of mJ.
Homework Equations
The Attempt at a Solution
since this is a nonlinear curve i thought that the area under the curve would equal the work done by the spring at the .15 m
so i integrated and got
-6x2 + 222.5x4
since the spring is starting at the equilibrium position, initial position is 0 and final position is .15m so
-6(.15)2+222.5(.15)4 = -.02235
this doesn't make sense since we are pulling the spring and the work should be positive right?