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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 wire of resistance 4 ohm is stretched to twice its original length.
- A meter stick of mass 400 g is pivoted at one end and displaced through an angle 60°.
- The frequency of an alternating voltage is 50 cycles per second and its amplitude
- If radius of earth’s orbit is made 1/4, the duration of a year will become
- A particle of mass m is driven by a machine that delivers a constant power k watts
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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