# Moment of inertia in plane translation

• arvindsharma

#### arvindsharma

I have a doubt in my mind regarding moment of inertia.in my textbook a question is somewhat like this The center of a disc of mass 'M' and radius 'R' is at a distance 'd' (here 'd' >'R') from a certain point 'O'.what is the moment of inertia of the disc about an axis perpendicular to the plane of the disc and passing through point 'O'?If,
(1)Disc is stationary
(2)Disc is having translatory motion such that perpendicular distance between center of disc and point 'O' remains same?
(3) disc is rotating about an axis perpendicular to its plane and passing through its center of mass?
(4)disc have both type of motions as in part 2 and part 3?

As far as i know moment of inertia is defined for rotation only so i could not answer part 1 and part 2(can i apply parallel axis theorem for first two parts?)for part 3 i applied parallel axis theorem and got right answer.unfortunately answer for part 4 was not even given in the book.can someone help me how to solve part 1,2 and 4th.
i will be thankful.