Question

(a)what minimum force F is needed to lift the piano (mass M) using the pulley aparatus in fig. 4-60 ?
(b)also determine the tension at each section of rope Ft1, ft2, ft3,ft4

Answer 1

(a) If we have a system of two pulleys, the force required will be

$$F=Mg/2.$$

(b) The tension in the rope directly attached to the piano is

$$F_{t4}=Mg.$$

$$F_{t3}=\frac{3}{2}Mg.\\\space\\ F_{t1}=F_{t2}=\frac{1}{2}Mg.$$