Question

A machine raises an object of weight 1200 N through a distance of 5.0 m. What is its efficiency if the energy input is 8 000 J?

Answer 1

Given

Weight of the object, W=1200 N

Distance travelled , s=5.0 m

Input energy, Q=8000J

To find

The efficiency of the engine

Explanation

The efficiency is the ratio of work done to the input energy

So

$\begin{gathered} \eta=\frac{W.s}{Q} \\ \Rightarrow\eta=1200\times\frac{5}{8000} \\ \Rightarrow\eta=0.75 \end{gathered}$

Conclusion

The efficiency is 0.75