Physics · Rotational Dynamics

JEE Main 2024 — 5 April, Shift 2 — Question 54

A hollow sphere is rolling on a plane surface about its axis of symmetry. The ratio of rotational kinetic energy to its total kinetic energy is x5\frac{x}{5}. The value of xx is \qquad .

Answer: 2

Numerical answer — enter this value.

Step-by-step solution

12Iω212Iω2+12mv2=(12)(23m2)ω2(12)(23mR2)ω2+12m(Rω)2\frac{\frac{1}{2} I \omega^{2}}{\frac{1}{2} I \omega^{2}+\frac{1}{2} m v^{2}}=\frac{\left(\frac{1}{2}\right)\left(\frac{2}{3} m^{2}\right) \omega^{2}}{\left(\frac{1}{2}\right)\left(\frac{2}{3} m R^{2}\right) \omega^{2}+\frac{1}{2} m(R \omega)^{2}}

=2323+1=25=\frac{\frac{2}{3}}{\frac{2}{3}+1}=\frac{2}{5} x=2\mathrm{x}=2

Answer key and solution verified before publishing.

Practise Rotational Dynamics

Start with this question, then two more from the same chapter — with a tutor that explains every step. Free.

Exam
JEE Main 2024
Subject
Physics
Chapter
Rotational Dynamics
Topic
Work-Energy Theorem in General Motion