NEET 2018 · PhysicsPrevious Year Question
The moment of the force F = 4î + 5ĵ + 6k̂ acting at the point (2, 0, -3), about the point (2, -2, -2), is:
Answer: (D) 17î - 4ĵ - 8k̂. Correct Answer (D): 17î - 4ĵ - 8k̂ Solution: r = (2,0,-3)-(2,-2,-2) = (0,2,-1).
- A.-7î + 8ĵ - 4k̂
- B.-4î - ĵ - 8k̂
- C.-8î - 4ĵ - 7k̂
- D.17î - 4ĵ - 8k̂✓
Correct Answer
(D) 17î - 4ĵ - 8k̂
Solution & Explanation
Correct Answer (D): 17î - 4ĵ - 8k̂ Solution: r = (2,0,-3)-(2,-2,-2) = (0,2,-1). τ = r×F = (2·6-(-1)·5, (-1)·4-0·6, 0·5-2·4) = (17, -4, -8) = 17î - 4ĵ - 8k̂. (Original option list mis-OCR'd '17' as '-7'.)
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