Refer to the diagram shown below.
The input force of 20 N should use the effect of the lever to lift the weight W on the other side of the fulcrum. Therefore the output force is equal to the weight lifted.
Moment balance about the fulcrum yields
W*0.5 - Fin*2 = 0
[tex](W \, N)*(0.5 \, m) - (20} \, N)*(2 \, m) = 0\\
W= \frac{40}{0.5}=80 \, N [/tex]
Because the output force is equal to W,
[tex]F_{out} = 80 \, N[/tex]
Answer: The output force is 80 N
