if woman lifts a 35kg child a distance of 1.5m and carries her forward 6.5 m.How much work does woman do in lifting how much work does child do?

1 Answer

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ndnordic | High School Teacher | (Level 2) Associate Educator

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Work is defined as a force moving through a distance.  Force in this case is the weight of the child being lifted = mg.

So the work done by the woman is mgh

35 kg * 9.81 m/s/s * 1.5 m = 515.025 J of work is done by the woman in lifting the child.

The child is doing no work while being lifted but does gain 515.025 J of potential energy because of the work done by the woman on the child.

Note that the woman does no additonal work in carrying the child forward 6.5 m.