Moment of inertia for this assembly

[Elias Waranoi]

Homework Statement

A slender rod is 80.0 cm long and has mass 0.120 kg. A small 0.0200-kg sphere is welded to one end of the rod, and a small 0.0500-kg sphere is welded to the other end. The rod, pivoting about a stationary, frictionless axis at its center, is held horizontal and released from rest. What is the linear speed of the 0.0500-kg sphere as it passes through its lowest point?

Homework Equations

I_p = I_cm + Md²
Moment of inertia slender rod I_r = ML²/12
-||- solid sphere I_s = 2/5 MR²

The Attempt at a Solution

I'm right around the corner to solve this, I just need to find the sum of the systems moment of inertia. I have the center of mass of the system, I also know that I have to use the parallel axis theorem but I don't have the radius of the small spheres so I don't know how I am supposed to calculate their moment of inertia.

Or should I be able to solve it without knowing the total moment of inertia?

 

[BvU]

You can consider the spheres as point masses on the basis of the term 'small' in the problem statement.

 

[Elias Waranoi]

Thanks! That was what I had to do!