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If a machine has an efficiency of 80% and it does 400 J of useful work, how much
Practice Questions
Q1
If a machine has an efficiency of 80% and it does 400 J of useful work, how much energy was supplied to the machine? (2023)
500 J
400 J
320 J
600 J
Questions & Step-by-Step Solutions
If a machine has an efficiency of 80% and it does 400 J of useful work, how much energy was supplied to the machine? (2023)
Steps
Concepts
Step 1: Understand that efficiency is a measure of how much useful work a machine can do compared to the total energy it uses.
Step 2: Write down the formula for efficiency: Efficiency = Useful Work / Total Energy Input.
Step 3: Rearrange the formula to find Total Energy Input: Total Energy Input = Useful Work / Efficiency.
Step 4: Plug in the values: Useful Work is 400 J and Efficiency is 80%, which is 0.8 in decimal form.
Step 5: Calculate Total Energy Input: Total Energy Input = 400 J / 0.8.
Step 6: Perform the division: 400 J divided by 0.8 equals 500 J.
Step 7: Conclude that the total energy supplied to the machine is 500 J.
Efficiency
– Efficiency is the ratio of useful work output to the total energy input, often expressed as a percentage.
Energy Calculation
– Understanding how to manipulate the efficiency formula to find total energy input based on given useful work and efficiency.
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