A uniform bar has two small balls glued to its ends. The bar is 2.00 m long and has mass 4.00 kg, while the balls each have mass 0.300 kg and can be treated as point masses. Find the moment of inertia of this combination about an axis (c) parallel to the bar through both balls;

Video transcript

Hello everyone. So in this problem we have two little balls which are bonded to the ends of a uniform bar. The balls can be thought of as point masses and have masses of 20.0.2 kilograms each. But the bar is three m long and has a mass of five kg. Find the combinations moment of inertia about an axis parallel to the bar. Cross both balls. So in this setup we have two balls which are bound buy somethin rod and the axis of rotation is across these balls. Now we know, find the rotational inertia. We simply use the equation the sum of the masses of the point objects, times the distance from the rotation squared. Now in this case, since it is parallel to the axis of the bar across both bars or balls are I will be zero for each point mass. So in this case I will simply just be zero kg times meters squared. His answer choice B. This is a very important distinction to make a great day.