CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

Two point masses A of mass M and B of mass 4M are fixed at the ends of a rod of length l and of negligible mass. The rod is set rotating about an axis perpendicular to its length with a uniform angular speed. The work required for rotating the rod will be minimum when the distance of axis of rotation from the mass A is at

A
25l
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
85l
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
45l

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
l5
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is C 45l


W=12Iω2

Let x be the distance of CM from A

I=Mx2+4M(lx)2

and if I is minimum, W will be minimum

dldx=2Mx+4M×2(lx)×(1)

=2Mx8M(lx)

dldx=10Mx8Ml

10Mx8Ml=0

x=45l

flag
Suggest Corrections
thumbs-up
0
similar_icon
Similar questions
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Speed and Velocity
PHYSICS
Watch in App
Join BYJU'S Learning Program
CrossIcon