a machine has an efficiency of 70%. how much work does the machine do when 20,000 j of work is done on…

a machine has an efficiency of 70%. how much work does the machine do when 20,000 j of work is done on it?\n14,000 j\n28,600 j\n1,400,000 j\n2,860,000 j

a machine has an efficiency of 70%. how much work does the machine do when 20,000 j of work is done on it?\n14,000 j\n28,600 j\n1,400,000 j\n2,860,000 j

Answer

Explanation:

Step1: Recall efficiency formula

The efficiency formula is $\text{efficiency}=\frac{\text{useful work output}}{\text{work input}}\times100%$. We know $\text{efficiency} = 70%=0.7$ and $\text{work input}=20000\ J$. We need to find $\text{useful work output}$.

Step2: Rearrange the formula

From $\text{efficiency}=\frac{\text{useful work output}}{\text{work input}}\times100%$, we can get $\text{useful work output}=\text{efficiency}\times\text{work input}$.

Step3: Substitute values

Substitute $\text{efficiency} = 0.7$ and $\text{work input}=20000\ J$ into the formula: $\text{useful work output}=0.7\times20000\ J = 14000\ J$.

Answer:

A. 14,000 J