http://www.ck12.org Chapter 6. Work and Energy
- If the woman holding the bag is walking at a constant speed, is she then doing work on the bag?
Answer:No, she’s not. The force she’s exerting on the bag is perpendicular to the direction of motion. It cannot
cause or impede the motion of the bag, so it can do no work upon it.
(Recall thatW= (Fcosθ)x,i fθ= 90 ◦,W=0.)