From 6e2 page 26:
Once he’s in position, use the basic “stopping moving objects” rules, above, to determine if he can get a hold on the object and start to slow it down. Typically, a character needs to have an appropriate Movement Power to stop a resisting object — a superhero who lacks Flight usually can’t Grab a flying object and use his STR to slow it down, since he has no way to counter its forward momentum. The GM may waive this rule in appropriate circumstances.