A block and tackle of six pulley is used to raise a load of 300N steadily through a height of 30m, if the workdone against friction is 2000j. Calculate;

1. The workdone by the effort

2. The efficiency of the system

3. The applied effort

work accomplished = 300*30

= 9,000 J

applied work = 9,000 + 2,000 = 11,000 Joules

efficiency = 100 * work accomplished/work applied

= (9/11) 100 = 81.8 %

force applied = (300/6) /.818

= 61.1 N

assuming that the 6 in your question refers to mechanical advantage