Same chapter3 marksDifficulty: Medium
Classify levers into three orders, giving one example of each.
Machines
3 marksDifficulty: Medium
Why does a class III lever always have a mechanical advantage less than one, and why is it still useful?
Original Khojo Papers practice question — not from a past board paper.
Answer
In a class III lever the effort is applied between the fulcrum and the load, so the effort arm is always shorter than the load arm and the mechanical advantage, which is the ratio of the two arms, is less than one. It is useful because the load then moves through a larger distance and at a greater speed than the effort does.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
The human forearm is a class III lever, which is why a small movement of the muscle moves the hand a long way.
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