Question

A weight lifter struggles but manages to keep a heavy barbell abovehis head. Occasionally he slips and the barbell starts to fall downward, but he always recovers. In each case, compare the force exerted by the weight lifter on the barbell to that exerted by the barbell on the weight lifter.

A)- With the barbell at rest.
B)- With the barbel moving upward.
C)- With the barbel moving downward.