Moment of Inertia,not hw problems, but trying to understand the concept better.

[sowmit]

The question says:
Imagine a solid disk, made of uniform material, a radius R and thickness L. What is the ratio of L/R if the moment of inertia of this disk about the axis passing through the center and perpendicular to the plane of the disk is the same as the moment of inertia about the axis passing through the center and parallel to the disk? [I definitely don't know how to answer this. I don't think I even understand how to start it off]

2nd Question says:
Is it possible to have a torque on an object while the net force applied to it is zero? If not, why not? If yes, give an example.

-> I said it is not possible because torque= Force * Sin(theta). Since force is 0, torque is o as well.

Can someone help me with these questions please?

 

[tiny-tim]

hi sowmit!

Imagine a solid disk, made of uniform material, a radius R and thickness L. What is theratio of L/R if the https://www.physicsforums.com/library.php?do=view_item&itemid=31" of this disk about the axis passing through the center and perpendicular to the plane of the disk is the same as the moment of inertia about the axis passing through the center and parallel to the disk?

you need to learn the common moments of inertia …

see http://en.wikipedia.org/wiki/List_of_moments_of_inertia

Is it possible to have a torque on an object while the net force applied to it is zero? If not, why not? If yes, give an example.

-> I said it is not possible because torque= Force * Sin(theta). Since force is 0, torque is o as well.

suppose there are two forces on the same object … can they have a https://www.physicsforums.com/library.php?do=view_item&itemid=175" if their net force is zero?