Why is the handle of a door fixed near the edge opposite the hinges?
ATo make the door visually balanced
BTo shorten the lever arm and conserve energy
CTo increase the moment about the hinges
DTo reduce friction in the hinges
Answer & Solution
Correct answer: C. To increase the moment about the hinges
1. Moment of a force equals force times the perpendicular distance from the pivot.
2. The hinges of a door are the pivot.
3. Placing the handle far from the hinges gives the longest lever arm.
4. For the same applied force, a longer arm produces a larger turning moment.
5. So less effort opens the door, making operation easier.
_Source: Selina Concise Physics ICSE Class 10, Ch 1 'Force' (icsehelp.com chapter extract)_
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