College Physics with MasteringPhysics 7th Edition by Jerry Wilson,Anthony Buffa,Bo Lou

Exercise 1

(a) As a weightlifter lifts a barbell from the floor in the "clean" procedure (Fig. a), has he done work Why or why not (b) In raising the barbell above his head in the "jerk" procedure, is he doing work Explain. (c) In holding the barbell above his head (Fig. b), is he doing more work, less work, or the same amount of work as in lifting the barbell Explain. (d) If the weightlifter drops the barbell, is work done on the barbell Explain what happens in this situation.


FIGURE Man at work See Conceptual.