CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon


Question

A thin square plate of side 3 m has mass 5 kg. Find the moment of inertia about axis AB as shown in figure.



A
15 kg-m2
loader
B
30 kg-m2
loader
C
45 kg-m2
loader
D
7.5 kg-m2
loader

Solution

The correct option is A 15 kg-m2
Given, mass of square plate (m)=5 kg
Side length of square plate (l)=3 m

To find moment of inertia of square plate about AB, let us consider an imaginary square of side 3 m adjacent to the given square plate as shown below.


Moment of inertia of complete rectangle about axis AB=ml212
where l is the length of rectangle =6 m
and m= mass of rectangle =10 kg

IAB for rectangle =10×(6)212=30 kg-m2
Therefore, by symmetry
IAB for square =30/2=15 kg-m2

Alternative method:
MoI of square about an axis passing through geometrical centre and parallel to the sides =ml212
Using parallel axis theorem, MoI about edge AB
IAB=ml212+m(l2)2
=ml23
=5×323=15 kg-m2

Physics

Suggest Corrections
thumbs-up
 
0


similar_icon
Similar questions
View More


similar_icon
People also searched for
View More



footer-image