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

A Force Fai3j6k Is Acting At A Point R2i6j12k The Physics Question

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. A car moves from X to Y with a uniform speed v(u) and returns to Y with a uniform speed
  2. A thin semicircular conducting ring (PQR) of radius r is falling with its plane
  3. Two metal wires of identical dimensions are connected in series. If σ₁ and σ₂ are
  4. A circular disc rolls down an inclined plane.The ratio of rotational kinetic energy
  5. If the length of a stretched string is shortened by 4% and the tension is increased

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.

NEETLab Mobile App

Share this page with your friends

Be the first to comment

Leave a Reply

Your email address will not be published.


*