Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
Concepts Of Physics MCQ Edition [Volume 1]
Exam
Concepts Of Physics MCQ Edition [Volume 1]
Subject
Physics
Chapter
Rotational Mechanics

Concepts Of Physics MCQ Edition [Volume 1] · Physics · Rotational Mechanics

A uniform rod with a mass of 0.50 kg and a length of 1 m has a...

A uniform rod with a mass of 0.50 kg0.50 \text{ kg} and a length of 1 m1 \text{ m} has a moment of inertia of 0.10 kg-m20.10 \text{ kg-m}^2 about an axis perpendicular to it. Determine the distance from this axis to the middle point of the rod.

Options

  1. A0.34 m0.34 \text{ m}
  2. B0.20 m0.20 \text{ m}
  3. C0.45 m0.45 \text{ m}
  4. D0.12 m0.12 \text{ m}

Correct answer

A. 0.34 m0.34 \text{ m}

Step-by-step solution

The moment of inertia of a uniform rod about an axis passing through its center of mass and perpendicular to its length is given by:

Icm=mL212I_{cm} = \dfrac{mL^2}{12}

Substituting the given values m=0.50 kgm = 0.50 \text{ kg} and L=1 mL = 1 \text{ m}:

Icm=0.50×(1)212=124 kg-m2I_{cm} = \dfrac{0.50 \times (1)^2}{12} = \dfrac{1}{24} \text{ kg-m}^2

According to the parallel axis theorem, the moment of inertia II about any parallel axis is:

I=Icm+md2I = I_{cm} + md^2

where dd is the distance from the axis to the center of mass (middle point) of the rod.

Given I=0.10 kg-m2I = 0.10 \text{ kg-m}^2, substituting the values gives:

0.10=124+0.50×d20.10 = \dfrac{1}{24} + 0.50 \times d^2

110−124=12d2\dfrac{1}{10} - \dfrac{1}{24} = \dfrac{1}{2} d^2

12−5120=12d2\dfrac{12 - 5}{120} = \dfrac{1}{2} d^2

7120=12d2\dfrac{7}{120} = \dfrac{1}{2} d^2

d2=760≈0.1167 m2d^2 = \dfrac{7}{60} \approx 0.1167 \text{ m}^2

d=0.1167≈0.34 md = \sqrt{0.1167} \approx 0.34 \text{ m}
Practice Rotational Mechanics on Quantrex Academy →

More from Rotational Mechanics

A wheel revolves about its axis with a uniform angular acceleration. Beginning from rest… Concepts Of Physics MCQ Edition [Volume 1]Starting from rest, a wheel is uniformly accelerated at 4 rad/s^2 for 10 seconds.… Concepts Of Physics MCQ Edition [Volume 1]Determine the angular velocity of a body rotating with an acceleration of 2 rev/s^2 as it… Concepts Of Physics MCQ Edition [Volume 1]A body rotates about a fixed axis with an angular acceleration of one… Concepts Of Physics MCQ Edition [Volume 1]A disc of radius 10 cm rotates about its axis with an angular speed of 20 rad/s .… Concepts Of Physics MCQ Edition [Volume 1]A disc of radius 10 cm rotates about its axis with an angular speed of 20 rad/s .… Concepts Of Physics MCQ Edition [Volume 1]A disc rotates about its axis with a uniform angular acceleration of 4 rad/s^2 .… Concepts Of Physics MCQ Edition [Volume 1]A block is suspended from a string wrapped on a disc of radius 20 cm , which is free to… Concepts Of Physics MCQ Edition [Volume 1] Full Rotational Mechanics list All Concepts Of Physics MCQ Edition [Volume 1] PYQs