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A man, of mass m, standing at the bottom...

A man, of mass m, standing at the bottom of the staircase, of height L climbs it and stands at its top.

A

Work done by all forces on man is equal to the rise in potential energy mgL.

B

Work done by all forces on man is zero.

C

Work done by the gravitational force on man is mgL.

D

The reaction force from a step does not dow work because the point of application of the force does nt move while the force exists.

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