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A force F=ai+3j+6k is acting at a point r=2i-6j-12k. The value of α for which angular momentum about origin is conserved is
Options
(a) 2
(b) zero
(c) 1
(d) -1
Correct Answer:
-1
Explanation:
From Newton’s second law for rotational motion,
τ = dL / dt, if L = constant then τ = 0
So, τ = r × F = 0
(2î – 6ĵ – 12k̂) × (αî + 3ĵ + 6k̂) = 0
Solving we get α = -1.
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Topics: Motion of system of Particles and Rigid Body
(73)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- A circuit contains an ammeter, a battery of 30 V and a resistance 40.8 ohm
- A voltmeter of range 2 V and resistance 300Ω cannot be converted into ammeter
- A radioactive substance has a half-life of four months. Three-fourth of substance
- For the radioactive nuclei that undergo either α or β decay, which one
- Two bullets are fired simultaneously, horizontally and with different speeds
Topics: Motion of system of Particles and Rigid Body (73)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
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