Answer: The efficiency of the lever is 80%.
Explanation:
An efficiency is the measure of how much wok or energy is conserved in a given process. It is defined as the ratio of output work and input work. If the energy is totally conserved in a process, the the percentage efficiency will be 100%.
Mathematically,
[tex]\%\text{ efficiency}=\frac{W_{out}}{W_{in}}\times 100[/tex]
Where,
[tex]W_{out}[/tex] = Work done by the lever = 20 J
[tex]W_{in}[/tex] = Work put in the lever = 25 J
Putting values in above equation, we get:
[tex]\%\text{ efficiency}=\frac{20}{25}\times 100\\\\\%\text{ efficiency}=80\%[/tex]
Hence, the efficiency of the lever is 80%.
