Question

A piece of chalk is going around a fixed axis 00' as shown in figure such that it takes equal amount of time in completing each revolution about 00' as well as about its own Axis AB. (which passes through its centre and is parallel to 00') What can be said about this type of motion of this chalk piece?

• A. Pure rotation
• B. Pure translation
• C. Pure rotation and translation
• D. Neither pure rotation nor pure translation

Answer 1

The correct option is A

Pure rotation

Here all the points of the body go around 00' in a circular fashion. Also the centre of all such circles lies on 00'.
Try to visualize.
Again the planes containing the individual circles are perpendicular to 00', and parallel to each other at all instants.

What do you think now?

Yes it is indeed pure rotational motion.