Discuss whether any work is being done by each of the following agents and, if so, whether the work is positive or negative. (a) a chicken scratching the ground a chicken does work on the ground. the ground does work on the chicken. no work is done. is the work positive or negative? the work is positive. the work is negative. no work is done. (b) a person studying (holding up a book but not moving it) the person does work on a book. the book does work on the person. no work is done. is the work positive or negative? the work is positive. the work is negative. no work is done. (c) a crane lifting a bucket of concrete the crane does work on the bucket. the bucket does work on the crane. no work is done. is the work positive or negative? the work is positive. the work is negative. no work is done. (d) the force of gravity on the bucket in part (c) the bucket does work on gravity. the force of gravity does work on the bucket. no work is done. is the work positive or negative? the work is positive. the work is negative. no work is done. (e) the leg muscles of a person in the act of sitting down the leg muscles do work on the individual. the individual does work on the leg muscles. the individual does work on the chair. no work is done. is the work positive or negative? the work is positive. the work is negative. no work is done.