A cord is wound round the circumference of wheel of radius r. The axis of the wheel is horizontal and the moment of inertial about it is I. A weight mg is attached to the cord at the end. The weight falls from rest. After falling through a distance 'h', the square of angular velocity of wheel will be:

Option 1 - <p><span class="mathml" contenteditable="false"> <math> <mrow> <mfrac> <mrow> <mn>2</mn> <mi>m</mi> <mi>g</mi> <mi>h</mi> </mrow> <mrow> <mi>I</mi> <mo>+</mo> <mi>m</mi> <msup> <mrow> <mi>r</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msup> </mrow> </mfrac> </mrow> </math> </span></p>
Option 2 - <p><span class="mathml" contenteditable="false"> <math> <mrow> <mn>2</mn> <mi>g</mi> <mi>h</mi> </mrow> </math> </span></p>
Option 3 - <p><span class="mathml" contenteditable="false"> <math> <mrow> <mfrac> <mrow> <mn>2</mn> <mi>g</mi> <mi>h</mi> </mrow> <mrow> <mi>I</mi> <mo>+</mo> <mi>m</mi> <msup> <mrow> <mi>r</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msup> </mrow> </mfrac> </mrow> </math> </span></p>
Option 4 - <p><span class="mathml" contenteditable="false"> <math> <mrow> <mfrac> <mrow> <mn>2</mn> <mi>m</mi> <mi>g</mi> <mi>h</mi> </mrow> <mrow> <mi>I</mi> <mo>+</mo> <mn>2</mn> <mi>m</mi> <msup> <mrow> <mi>r</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msup> </mrow> </mfrac> </mrow> </math> </span></p>
2 Views|Posted 4 months ago
Asked by Shiksha User
1 Answer
A
4 months ago
Correct Option - 1
Detailed Solution:

mg – T = ma       . (1)

T * R = l a               . (2)

a = a R                    . (3)

With the help of equations (1), (2) and (3), we get

-> a = m g m + l R 2  

v = 2 a h = ω R  

ω 2 = 2 m g h l + m R 2     

 

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Physics System of Particles and Rotational Motion 2025

Physics System of Particles and Rotational Motion 2025

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