Why Is Inertia Crucial in Understanding Rotational Motion?

[ted.hb]

Why do we use inertia in rotational motion and not the whole mass of an object ?

 

[Doc Al]

Why do we use inertia in rotational motion and not the whole mass of an object ?

What do you mean?

Do you mean rotational inertia? (Moment of inertia.) If so, realize that rotation and translation have their differences.

 

[ShayanJ]

I remember any introductory text on the subject gives enough arguments and calculations!
Grant R. Fowles' Analytical mechanics is enough I think.

 

[Pythagorean]

The moment of inertia is a calculation that does consider the whole mass of the object, as well as some information about the distribution of the mass about the rotational axis.