Question

A pulley system has five pulleys in all and is 75% efficient. Calculate a, MA b. an effort required to lift a load of 875 N c. he resistance due to movable parts of the pulley system.

Answer 1

Dear Student,

(a)
V.R=number of pulleys=5
$$\begin{gathered} M.A=\eta \left(V.R\right) \\ =0.75\left(5\right) \\ =3.75 \end{gathered}$$

(b)
$$\begin{gathered} \frac{L}{E}=M.A \\ E=\frac{L}{M.A} \\ =\frac{875}{3.75} \\ =233.33N \end{gathered}$$

(c)
calculate resistance due to movable part of the pulley system.

M.A	=	V.R. –(x/E)
x	=	E (V.R. – M.A.)

$$\begin{gathered} x=233.33(5-3.75) \\ =291.7 \end{gathered}$$

Regards,