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By lubricating the pulley, the work needed was decreased from 50 J down to
44 J. The output work of the pulley remained 40 J.
The efficiency of the pulley AFTER lubrication is

Respuesta :

Before lubrication:

[tex]\tt \dfrac{40}{50}\times 100\%=80\%[/tex]

The efficiency of the pulley after lubrication becomes:

[tex]\tt \dfrac{40}{44}\times 100\%=91\%[/tex]