Question

determine the useful energy output of a simple machine with 90 percent efficiency if the total energy input is 200 joules? view available hint(s) 100 joules 1800 joules 200 joules 180 joules submit provide feedback

Explanation:

Step1: Recall efficiency formula

Efficiency ($\eta$) is given by $\eta = \frac{\text{Useful Energy Output (} E_{out} \text{)}}{\text{Total Energy Input (} E_{in} \text{)}} \times 100\%$. We need to find $E_{out}$.

Step2: Rearrange formula for $E_{out}$

From $\eta = \frac{E_{out}}{E_{in}} \times 100\%$, we can rearrange to $E_{out} = \frac{\eta \times E_{in}}{100\%}$.

Step3: Substitute values

Given $\eta = 90\%$, $E_{in} = 200$ Joules. Substitute into the formula: $E_{out} = \frac{90\% \times 200}{100\%}$.

Step4: Calculate

$90\%$ is $0.9$ in decimal. So $E_{out} = 0.9 \times 200 = 180$ Joules.

Answer:

180 Joules (corresponding to the option: 180 Joules)