A force F=ai+3j+6k is acting at a point r=2i-6j-12k. The value of α for

⇦

⇨

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.

Related Questions:

1. The wavelength of X-rays is in the range
2. An explosion breaks a rock into three parts in a horizontal plane
3. When 4 A current flows for 2 min in an electroplating experiment,
4. The electric field in a certain region is acting radially outward and is given by E=Ar.
5. A particle of mass m oscillates along x-axis according to equation x = a sin ?t

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

18000+ students are using NEETLab to improve their score. What about you?

Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.

---

Share this page with your friends