A15.0-lb block rests on the floor. (a) what force does
the floor exert on the block? (b) a rope is tied to the
block and is run vertically over a pulley. the other end
is attached to a free-hanging 10.0-lb object. what now
is the force exerted by the floor on the 15.0-lb block?
(c) if the 10.0-lb object in part (b) is replaced with a
20.0-lb object, what is the force exerted by the floor on
the 15.0-lb block?