(a) Here, F = mg = 250 x 10 N,
S = 1 m
Work done is given by W = F x S .
= 2500 N x 1 m = 2500 J
(b) No work is done in just holding the weight because there is no displacement
i.e., S = 0, W = FS = 0.
(c) They get tired because of muscular effort that they have to apply in supporting the weight.