[填空题]
A window washer pulls herself upward using t tt80kb5ct/aq4.+h havcfm:: m /jgpfhe bucket-pulley apparatus s:mork, impt0p g(;j :shown in Fig. 4-48. (a) How hard must she pull downward to raise hersoig p;0:tjm rk:s( ,mpelf slowly at constant speed?
(b) If she increases this force by 15 % , what will her acceleration be? The mass of the person plus the bucket is 65 kg .
