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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
- In an a.c circuit the e.m.f. (e) and the current (i) at any instant are given
- Two metallic spheres of radii 1 cm and 3 cm are given charges of -1 x 10⁻² C
- A vertical spring with force constant k is fixed on a table. A ball of mass
- Steam at 100⁰C is passed into 20 g of water at 10°C. When water acquires a temperature
- A block of mass 4 kg is kept on a rough horizontal surface.The coefficient of static
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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