[填空题]
A window washer pulls herself 2o/cv;v pcm7 uea+vd 8z-eqgc 041ojfupward usc 7lp7h -rcp9eing the bucket-pulley apparatus shown in Fig. 4-48. (a) How hard must she pull downward to raise herse r p-hc7l9ep7clf 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 .
