Discuss whether any work is being done by each of the following agents and, if so, whether the work is positive or negative
(i) a chicken scratching on the ground
(ii) a person studying physics
(iii) a crane lifting a bucket of concrete
(iv) the gravitational force on the bucket in (iii)
(v) the leg muscles of a person in the act of sitting down
1.All of them do work. Positive work is done in cases (i), (ii), and (iii) and negative work is done in cases (iv) and (v).
2.No work is done in case (ii). Positive work is done in cases (i) and (iii) and negative work is done in cases (iv) and (v).
3.No work is done in cases (i) and (ii). Positive work is done in case (iii) and negative work is done in cases (iv) and (v).
4.No work is done in cases (i) and (ii). Positive work is done in cases (iii) and (v) and negative work is done in case (iv).
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