Recent content by blr

Thank you...

Mass of hollow cube is given. So that is mass of full cube, before removing inner cube with edge length b.

anyone?

So... I(of hollow cube) = m * \frac{a^3}{a^3-b^3} * \frac{a^2}{6} - m * \frac{b^3}{a^3-b^3} * \frac{b^2}{6} that is \frac{m(a^5-b^5)}{6(a^3-b^3} Is that ok?

d a^3

? a^3

I know that, but I don't know how to do it :( Thanks for your answers!

I know mass of hollow cube, and it is m... Moment of inertia of cube is m a^2/6. So moment of inertia of hollow cube is m1 a^2/6 - m2 b^2/6... I need help with m1 and m2...

Homework Statement How to calculate moment of inertia of hollow cube. Homework Equations The Attempt at a Solution I guess that subtracting the moment of inertia of the inner cube from the moment of inertia of the outer cube is wrong. Even it is close to solution, what mass to put in...