A box is lifted vertically 1.5 m and is then held there. The box has a weight of 100 N. Ignore friction. How much work is being done lifting the box? 150 J

50 J

100 J

0 J

The answer is 4f======since electrostatic force is given by    we let f be the electrostatic force when  r = 1 m    if we let  denote the electrostatic force when the distance is decreased so that r = 0.5m, then    we established earlier that f = kq₁q₂. therefore    the force will now be 4f.

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