Question

Calculate the (i) velocity ratio (ii) mechanical advantage (iii) % efficiency of a machine which overcomes a resistance of 800 N through a distance of 0.12 m, when an effort of 160 N acts through a distance of 0.72 m ?

Answer 1

Dear Student,

$$\begin{gathered} \mathrm{L}=800\mathrm{N} \\ \mathrm{d}=0.12\mathrm{m} \\ \mathrm{E}=160\mathrm{N} \\ \mathrm{D}=0.72\mathrm{m} \\ \left(1\right)\mathrm{Velocity}\mathrm{ratio},\mathrm{VR}=\frac{\mathrm{D}}{\mathrm{d}} \\ \mathrm{Velocity}\mathrm{ratio},\mathrm{VR}=\frac{0.72}{0.12}=6 \\ \left(2\right)\mathrm{Mechanical}\mathrm{Advantage},\mathrm{MA}=\frac{\mathrm{L}}{\mathrm{E}} \\ \mathrm{MA}=\frac{800}{160}=5 \\ \left(3\right)\%\mathrm{efficiency}=\frac{\mathrm{MA}}{\mathrm{VR}}\times 100\% \\ \%\mathrm{efficiency}=\frac{5}{6}\times 100\%=83.33\% \end{gathered}$$