Question

Is the work done zero if we have thrust?

Answer 1

If the question is meant as “opposing forces of equal magnitude”, the work done is zero. This is because, for two equal and opposite forces, the resultant force becomes zero. It is obvious that zero force causes zero displacement. So, the product of zero force with zero displacement results in zero work.

Answer 2

Answer:

If you have a force dF normal to the surface then any displacement lying in the surface will be normal to dF and therefore the work done will be zero.In this case the motion of the rocket is also normal to the surface, i.e. parallel to the thrust, so the work done is not zero.

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Answered By Legend Akhil