To find the efficiency of the hair dryer, we can use the formula for efficiency:
\[ \text{Efficiency} = \frac{\text{Useful Output Energy}}{\text{Input Energy}} \times 100% \]
In this case, the useful output energy can be considered as the kinetic energy output, heat energy output, and sound energy output combined. However, typically, the useful output energy would just refer to the useful energy that accomplishes the task at hand, which might focus only on the kinetic energy if that is what is considered useful for the operation of the hair dryer.
Let's calculate the total output energy:
\[ \text{Total Output Energy} = \text{Kinetic Energy} + \text{Heat Energy} + \text{Sound Energy} \] \[ \text{Total Output Energy} = 110J + 350J + 40J = 500J \]
Now we can calculate the efficiency:
\[ \text{Efficiency} = \frac{500J}{500J} \times 100% = 100% \]
However, usually, the useful output is what contributes effectively—for a hair dryer, that may not typically be all forms of energy. If we focus only on kinetic (which might be considered the primary useful form for moving air), we can do the calculation again by using just the kinetic energy:
\[ \text{Efficiency (based on kinetic output)} = \frac{\text{Kinetic Output}}{\text{Input Energy}} \times 100% \] \[ \text{Efficiency} = \frac{110J}{500J} \times 100% = 22% \]
Thus, if we only consider kinetic energy as the useful output energy, the efficiency of the hair dryer is 22%. If we consider all output, then it appears to be 100%, but this typically wouldn’t reflect practical efficiency from an operational perspective.
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