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supposed to vacuum cleaner uses 120 J of electrical energy. If 45 J used to pull air into a vacuum cleaner, how efficient is the vacuum cleaner?

Verified Answer :

calculista

we know that

Power efficiency is defined as the ratio of the output power divided by the input power:

so

\(efficiency =\frac{ Power\ out}{Power\ in} *100\)

in this problem

\(Power\ out=45J\\ Power\ in=120J\)

Substitute in the formula above

\(efficiency =\frac{ 45}{120} *100\)

\(efficiency =37.5\)%

therefore

the answer is

the efficient is \(37.5\)%

ysabayomi

Answer:

The efficiency of the vacuum cleaner is 37.5%

Explanation:

The efficiency of a machine can be calculated as

Efficiency = (work output ÷ work input) × 100%

Work output (according to the question) is 45J of electrical energy

work input (according to the question) is 120J of electrical energy

Efficiency = (45 ÷ 120) × 100

Efficency = 37.5 %

The efficiency of the vacuum cleaner is 37.5%

NOTE: Vacuum cleaner is a machine and a machine can not be 100% efficient

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