Your tired 10 lb. baby cousin is cradled in your arm as you're walking back and forth across a 15m room to get her to fall asleep. Explain what work was done on the baby.
Over and over and over ...
Same question, different words :
https://www.jiskha.com/questions/1778287/When-a-block-is-dragged-across-a-table-by-a-string-that-is-parallel-to-the-surface