Account for useful output and efficiency
See this course’s project requirements
An energy-accounting notebook explaining work, stored energy, efficiency and three heat-transfer mechanisms in supplied desk scenarios.
Keep your working files in your own notebook or software. Save a private description, checklist, and work link in My Proof.
What to include
- Account for useful and dispersed stores within a boundary.
- Calculate work with constant parallel force conditions.
- Calculate gravitational energy change using supplied g and height differences.
- Compare efficiencies with the same useful-output definition.
- Classify three heat-transfer routes.
- Compare supplied thermal designs with limits and complete all changed cases.
Review and revise
Use these criteria to check your work and choose what to improve.
- Method: applies the course-specific rules to the supplied cases with visible intermediate work.
- Accuracy: results agree with the stated facts, units, boundaries and independent checks.
- Reasoning: explains why the result follows and identifies a limitation or unresolved question.
- Transfer: completes changed cases and revises the final project when a relevant assumption changes.
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The idea in everyday life
Fictional paper motor record: electrical input 500 J; useful mechanical output 300 J; thermal and sound outputs together 200 J. Goal is mechanical movement. No device inspection, wiring or purchase is required.
An efficiency fraction compares the specified useful output energy with input energy: useful/input. The useful label depends on the task. A low useful fraction does not mean energy is destroyed; other outputs must be accounted for. Compare records using the same output definition.
Account for useful output and efficiency — worked practice
An efficiency fraction compares the specified useful output energy with input energy: useful/input. The useful label depends on the task. A low useful fraction does not mean energy is destroyed; other outputs must be accounted for. Compare records using the same output definition.
Fictional paper motor record: electrical input 500 J; useful mechanical output 300 J; thermal and sound outputs together 200 J. Goal is mechanical movement. No device inspection, wiring or purchase is required.
1. 1. Define
State the input and useful task.
You should see: 500 J electrical input; 300 J mechanical movement is defined as useful.
2. 2. Calculate
Divide useful output by input.
You should see: 300/500=0.60 or 60 percent.
3. 3. Balance
Account for other outputs.
You should see: 300+200=500 J; no supplied energy is missing.
4. 4. Compare
Evaluate a changed design with same 500 J input and 350 J useful output.
You should see: 350/500=70 percent; 150 J remains in other outputs under the supplied ledger.
What to finish
An input/output ledger with two comparable efficiency fractions.
Watch for this
A heater and motor can define useful output differently. A meaningful comparison keeps the task and accounting definition consistent.
How can I tell I understand it?
Calculate a changed efficiency without implying that dispersed energy was destroyed.
Quick knowledge check
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Source & access notes · checked 2026-10-01
Web open/search showed the official page, its topic heading and relevant concept description. This is a content/source check, not a provider endorsement.
Access: Official page retrieved with the web reader on 2026-10-01; interactive tools and videos were not certified by retrieval.
Reuse: Original fictional teaching cases, calculations, questions and examples; link and short factual paraphrase only. No copied source exercises or illustrations.
Source & access notes · checked 2026-10-01
Web open/search showed the official page, its topic heading and relevant concept description. This is a content/source check, not a provider endorsement.
Access: Official page retrieved with the web reader on 2026-10-01; interactive tools and videos were not certified by retrieval.
Reuse: Original fictional teaching cases, calculations, questions and examples; link and short factual paraphrase only. No copied source exercises or illustrations.
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