Consider a spring that does not obey Hooke's law very faithfully. One end of the spring is fixed. To keep the spring stretched or compressed an amount x, a force along the x-axis with x-component Fx=kx−bx2+cx3 must be applied to the free end. Here k=100N/m, b=700N/m2, and c=12000N/m3. Note that x>0 when the spring is stretched and x<0 when it is compressed.

The work done will be 0.115 J.

Explanation:

Given that,

A force along the x-axis with x-component,

Suppose, How much work must be done to stretch this spring by 0.050 m from its unstretched length?

We need to calculate the work done

Using formula of work done

Put the value into the formula

Put the value of k,b,c and x

Hence, The work done will be 0.115 J.

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explanation:

the answer is b ) square root of 5