CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
Question

A system of solid discs, each of mass M and radius R is shown in figure.


Find the MOI about an axis passing through point O and perpendicular to the plane.

A
9MR22
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
9MR2
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
18MR2
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
27MR2
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution

The correct option is D 27MR2
This is a regular hexagon made by joining all the disc centers whose every edge is equal to 2R.


The moment of inertia of solid disc about its center and perpendicular to its plane is
I=MR22
Here, distance of each of the points from point O is 2R each. Hence MOI will be same for all the discs about point O.
Therefore,
I=I1+I2+I3+I4+I5+I6
I=6×I1
I=6×[MR22+M(2R)2]
I=6×[9MR22]
I=27MR2

flag
Suggest Corrections
thumbs-up
0
BNAT
mid-banner-image