InterviewSolution
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InterviewSolution
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A force `F=-k(y hati + x hatj)` (where k is a positive constant) acts on a particle moving in the `x-y` plane. Starting from the origin, the particle is taken along the positive x-axis to the point `(a,0)` and then parallel to the y-axis to the point `(a,a)`. The total work done by the force F on the particle is (a) `-2ka^(2)` , (b) `2ka^(2) , (c)`-ka^(2)` , (d) `ka^(2)`A. `-2ka^2`B. `2ka^2`C. `-ka^2`D. `ka^2` |
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Answer» Correct Answer - C `dW=vecF.dvecr=-k(yhati+xhatj)xx(dxhati+dyhatj)` `=-k[ydx+xdy]=-kd(xy)` `W=-kint_(0.0)^(a,a)d(xy)=-k|xy|_(0,0)^(a,a)` |
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