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A simple machine does 30 J of work with an efficiency of 28%. How much energy was put into the machine?

A simple machine does 30 J of work with an efficiency of 28%. How much energy was-example-1
User Charmae
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1 Answer

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Take into account that efficiency is given by the following expression:


\text{ efficiency=(output work/input work)}\cdot100

In this case, you have:

efficieny = 28%

output work = 30J

input work = ?

Replace the previous values of the parameters into the formula for efficieny, solve for input work and simplify:

28% = (30J/input work)*100%

input work = 30J*(100% / 28%)

input work = 107.14 J

Hence,about 107.14 J was put into the machine

User Markstar
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