A couple consists of two equal and opposite forces of 4 N each, separated by 0.30 m. The moment of the couple is:
A1.2 Nm
B0.6 Nm
C2.4 Nm
D0.8 Nm
Answer & Solution
Correct answer: A. 1.2 Nm
1. Moment of a couple equals one of the equal forces multiplied by the perpendicular separation between them.
2. Given F = 4 N and separation d = 0.30 m.
3. Moment = F × d = 4 × 0.30 = 1.2 Nm.
4. The sign depends on direction; the magnitude is 1.2 Nm.
5. Options A and C come from forgetting to multiply by 2 or doubling unnecessarily.
_Source: Selina Concise Physics ICSE Class 10, Ch 1 'Force' (icsehelp.com chapter extract)_
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