Bootstrap Elevator

Study the drawing carefully. Can the man lift both himself and the block off the ground?

 

Although it looks as if the man were trying to lift himself up by his own bootstraps, he really isn't. True, for every pound of force that he pulls up on the rope, he also pushes down an equal force on the block, but if he is strong enough to lift his own weight plus the weight of the block, he will rise from the ground. (Tests have shown that a 190-pound man can lift both himself and a 110-pound block in this way.)