(a) As a weightlifter lifts a barbell from the floor in the clean procedure (Fig. 5.25a), has...

(a) As a weightlifter lifts a barbell from the floor in the €œclean€ procedure (Fig. 5.25a), has he done work? Why or why not?

(b) In raising the barbell above his head in the €œjerk€ procedure, is he doing work? Explain.
(c) In holding the barbell above his head (Fig. 5.25b), 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 bar-bell? Explain what happens in this situation.

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