Answer: 63 J
Explanation:
The effiency ([tex]E[/tex]) of a machine is given by the ratio between the output work [tex]W_{out}[/tex] and the input work [tex]W_{in}[/tex]:
[tex]E=\frac{W_{out}}{W_{in}}[/tex]
Where:
[tex]E=84\%=0.84[/tex]
[tex]W_{in}=75 J[/tex]
Isolating [tex]W_{out}[/tex]:
[tex]W_{out}=E W_{in}[/tex]
[tex]W_{out}=(0.84)(75 J)[/tex]
Finally:
[tex]W_{out}=63 J[/tex]
