Leb said:
tiny-tim said:Hi Leb!
I don't really understand what's worrying you.
don't "the axis tangent to the disk at Q" and "parallel to a tangent vector to Q" mean the same thing?
Principal axes for a disc refer to the three mutually perpendicular lines that define the orientation and rotation of a disc. These axes are known as the principal axes of inertia and are used to describe the movement and stability of a rotating disc.
The principal axes for a disc are determined by calculating the moments of inertia along each axis. The axis with the largest moment of inertia is the disc's principal axis of rotation. The other two axes are perpendicular to this axis and are known as the principal axes of inertia.
Knowing the principal axes for a disc is important in understanding its movement and stability. The disc will rotate most easily around its principal axis of rotation and will be more resistant to rotation around the other two axes.
Yes, the principal axes for a disc can change if the disc's shape or mass distribution is altered. However, for a symmetrical disc with uniform mass distribution, the principal axes will remain constant.
Principal axes for a disc are used in engineering and physics to analyze the movement and stability of rotating objects. They are also important in fields such as robotics and aviation, where understanding the principal axes of a disc-shaped object is crucial for designing and controlling its movement.