Question

The rotational inertia I of a solid sphere is two fifths of the product of the sphere's mass M and it's radius squared r²?

I need help expressing the problem algebraically

Answer 1

`I = 2/5MR^2`

Explanation:

Let
R= radius
M = mass
`I` = rotational inertia

Radius squared means `R^2`

Product of `A and B = A*B = AB`, therefore
product of mass and its radius squared `= M *R^2 = MR^2`

Two fifth of `A and B= 2/5 ( A*B) = 2/5 AB`

Put them all together:

`I = 2/5 Mr^2`