Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert

The toy-top (initially at rest) shown in the figure, has a moment of inertia 4×10-4 kg m2 and it is free to rotate about the stationary axis AA'. The string wrapped around the peg of the toy-top is pulled outwards without letting it slip and simultaneously maintaining a constant tension of 5.625 N. If ω is the angular speed (in rad s-1) of the top after 80 cm of string has been pulled off the peg, then mark your answer as ω100. If your answer is K, mark 2K as answer after rounding off to nearest integer.

PhysicsRotational MotionJEE Main
Solution:
2197 Upvotes Verified Answer
The correct answer is: 3
Work done
=F×Δr=5.625×0.8m=4.5J and
work done =ΔK= 1 2 r 2 1 2 1 2
4.5= 1 2 ×4× 10 4 × ω r 2 0
... ( top starts from rest, ω i =0 )
ω f =150rad/s

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.