In "Contents of the Dead Man's Pocket," how does the description of Tom waiting for the yellow paper to move generate suspense?

The reader is well aware that Tom cannot commit himself to going out on the ledge after the yellow sheet until he knows what the yellow sheet itself is going to do. There are several possibilities. It could get stuck somewhere on or near the ledge. It could suddenly take off like a bird and go flying off into the sky above the tall buildings of Manhattan. Or it might do what he is hoping it will do.

He knelt at the window and stared at the yellow paper for a full minute or more, waiting for it to move, to slide off the ledge and fall, hoping he could follow its course to the street, and then hurry down in the elevator and retrieve it. 

Tom knows that if he is going to risk his life he ought to be risking it for a sensible purpose. He doesn't want to get out there on the ledge and suddenly see his precious paper take off and fly away. The author increases the suspense by keeping the reader wondering, not only what Tom is going to do, but what the paper is going to do. The paper seems to have a life of its own. It seemed so even while it was still inside the apartment. Tom didn't know whether it was going to remain plastered against the glass and wood of the window or whether it would decide to thwart him by flying outside. There are many occasions when it seems as if inanimate objects are deliberately teasing or tormenting us. Someone has called this "the perversity of inanimate objects."

Tom is not going out on that ledge as long as the yellow paper keeps scudding along it. He would be playing cat and mouse with it. He is not going out on the ledge if he sees it fly away, as it well could do. That would seem like the hand of Fate, telling him his project would not bring him the glory he hoped for but might bring ridicule and disgrace. Tom is not going out on the ledge, of course, if the paper falls to the street. He would be making a made rush down to the street, hoping against hope the paper would land on the sidewalk and not take off again and lead him on a mad chase up the middle of Lexington Avenue with horns honking and brakes shrieking. 

The reader is temporarily relieved when it appears that the paper has made up its mind to stay in one place and give Tom a chance to catch it.

...and then he saw that the paper was caught firmly between a projection of the convoluted corner ornament and the ledge. 

The suspense is temporarily lulled. Tom's alternatives are narrowed down to two. He can either go after the paper or try to forget about it. Then he yields to a sudden mad impulse and climbs out onto the ledge--and the real suspense begins!