Work done by a variable force o
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The variable force is more commonly encountered than the constant force .
If the displacement Dx is small , we can take the force F ( x ) as approximately constant and the work done is then DW = F ( x ) Dx
For total work , we add all work done along small displacements .
Example : A force F = 3x 2 start acting on a particle which is initially at rest . Find the work done by the force during the displacement of the particle from x = 0m to x = 2m .