Question

The law of a certain lifting machine is $P=W/50+1.5$. The velocity ratio of the machine is 100. Find the maximum possible mechanical advantage and maximum possible efficiency of the machine

• A. 50 and 50%
• B. 50 and 60%
• C. 60 and 60%
• D. 60 and 50%

Answer 1

Answer: (A)

50 and 50%

$\begin{array}{c}\text{given}\\ \text{the law of machine,}P=W/50+1.5\\ \text{slope,}m=\frac{1}{50}\\ \begin{array}{c}\text{W.}A=\frac{1}{m}=50\\ \text{and max efficiency}\eta max=\frac{m\cdot A}{V\cdot R}\times 100\%\end{array}\end{array}$

$\begin{array}{cc}\text{where}& v\cdot R=100\\ \therefore {\eta }_{max}& =\frac{50}{100}\times {100}^{\circ }J\\ & =50\%\end{array}$

Ans; Option A