moment inertia

1. Does friction torque in speeding up = speeding down?

On speeding up: τload - τfriction = Iαup On speeding down: τfriction = Iαdown If i substitute τfriction from speeding down to speeding up equation, i get moment of inertia: I = (τload)/(αup+αdown) But, is this allowed? Does friction torque in speeding up is equal to friction torque in...
2. A basic question about rotation

Problem Statement: Let there be a ring of mass m and radius r. Let 3 masses be attached to the ring and named as O,P and Q. Mass of O and Q is 2m and mass of p is M. The angle between 2 masses is 15 degrees as shown in the figure. Find the maximum velocity the ring must roll so that it doesn't...
3. Experimental determination of the moment inertia of a sphere

Hello, I was recently given the task to find experimentally the moment inertia of a sphere. I thought of rolling the sphere down an inclined plane and applying conservation of energy to the sphere. The equations i came up with are: mgh = 1/2mv2 + 1/2Iω2 solving for v^2 we come up with the...
4. I General approach to find principal axes of rotation?

Suppose i have an equilateral triangle and i want to find the principal axes of rotation passing through one of the vertex. How can i do that? I am thinking along the following lines but i'm not too sure: 1)Since the equilateral triangle has symmetry about a median, that definitely is one...
5. Moment of Inertia of a Spinning Record with a Hole in Center

1. Homework Statement A 45 RPM record is a disk with a wide hole in the center. The mass of such record is 45g. It is 7 inches in diameter, and the hole in the center has a 1.5 inch diameter. (Sorry for the odd units, this was the way it was given). Find the moment of inertia of the 45 RPM...
6. Application of integrals to find moment Inertia

I need to make a project that integrates physics with math, involving the use of integrals to find moment inertia of areas. The theory could be read here :http://www.intmath.com/applications-integration/6-moments-inertia.php I need to make an object that applies the theory above. Can anybody...