Trick to calculate Moment of Inertia

 For Round Shapes:

GENERAL FORMULA:

MR^2

FOR LINEAR SHAPES:

GENERAL FORMULA:

ML^2

TYPES OF ROUND SHAPE:

1)HALLOW CYLINDER

FORMULA :MR^2

2)Ring

FORMULA :MR^2

3)Solid Cylinder

FORMULA :MR^2/2

4)Disc

FORMULA :MR^2/2

5)Sphere

2/5MR^2

6)Hoop

MR^2/2

Linear shapes :

1)Rod (thin) 

Ml^2/12,