Question

A system of pulleys is used to lift a load of $1000k{g}_{wt}$. If the efficiency of the pulley system is $80\%$ and velocity ratio is $20$, find the effort required to lift the load.

Answer 1

Step 1: Given data

$$\begin{gathered} Load\left(W\right)=1000k{g}_{wt} \\ Efficiency\left(\eta \right)=80\%or\frac{80}{100}=0.8 \\ Velocityratio(V.R)=20 \end{gathered}$$

Step 2: Finding the effort required to lift the load

$$\begin{gathered} Efficiency=\frac{Mechanicaladvantage}{Velocityratio} \\ Mechanicaladvantage(M.A)=\eta \times V.R \\ (M.A)=0.8\times 20=16 \end{gathered}$$

$$\begin{gathered} M.A=\frac{load}{effort} \\ Hence,effort=\frac{load}{Mechanicaladvantage}=\frac{1000}{16}=62.5k{g}_{wt} \end{gathered}$$

Thus, the effort required to lift the load is $62.5k{g}_{wt}$.