Question

The efficiency of a squeaky pulley system is 73 percent. The pulleys are used to raise a mass to a certain height. What force is exerted on the machine if a rope is pulled 18.0 m in order to raise a 58 kg mass a height of 3.0 m

Answer 1

129.9 m

Step-by-step explanation:

Efficiency is the ratio of work output to work input, expressed as a percentage.

`Efficiency= \frac {W_(out)}{W_(in)}`

We know that work= mgh hence to get the work input

`W_(in)= \frac {58* 9.81* 3}{0.73}=2338.273973 J`

Work done by applied force=Fd

Fd=2338.273973 J

we have d as 18 m hence
`F=\frac {2338.273973 J}{18}=129.9041096 m\approx 129.9 m`