Same chapter3 marksDifficulty: Medium
Why does a class III lever always have a mechanical advantage less than one, and why is it still useful?
Machines
3 marksDifficulty: Medium
Why is the efficiency of a practical machine always less than 100%?
Original Khojo Papers practice question — not from a past board paper.
Answer
Part of the work put into a machine is used up against friction between its moving parts and in lifting the movable parts of the machine itself. That work does not appear as useful work on the load, so the work got out is always less than the work put in.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
Lubrication reduces friction and so raises the efficiency, but it can never remove it entirely.
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