[填空题]
A box weighing 77.0 N rests on a table. A rope tied to bdb,zw 2*qysh4 mi*4 d mhn9,p/c vh/pi+vhd99 -znliq z)d9fthe box runs vertically upward over a pulley and a weight is hung from the other end (Fig. 4-40). Dete li-qd9f)znz9rmine the force that the table exerts on the box if the weight hanging on the other side of the pulley weighs
(a) 30.0 N ,
(b) 60.0 N ,
(c) 90.0 N .
