Work Energy And Power Question 146

Question: When a rubber-band is stretched by a distance x , it exerts a restoring force of magnitude F=ax+bx2 , where a and b are constants. The work done in stretching the unstretched rubber band by L is,

Options:

A) aL22+bL33

B) 12(aL22+bL33)

C) aL2+bL3

D) 12(aL2+aL3)

Show Answer

Answer:

Correct Answer: A

Solution:

[a] Restoring force on rubber-band, F=ax+bx2

Work done in stretching the rubber-band by a small amount dx,dW=Fdx

Net work done in stretching the rubber-band by L is

W=dW=0LFdx=0L(ax+bx2)dx

W=[ax22+bx33]0L=aL22+bL33



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