Thread: Rod in freefall
View Single Post
Nov22-12, 03:25 AM
P: 1,005
This has been brought up numerous times but I don't really understand it. Consider a rod in freefall.
If you put your coordinate frame in the center of mass of the rod, there will be no torque around it and the rod as a whole will follow a straightline down. But now put a coordinate frame on one of the end points. Apart from the gravity pulling down on the rod as a whole, there will now be a net torque on the rod (because gravity acts in the center of mass).
What goes wrong with this picture, because clearly the rod doesn't rotate!
Phys.Org News Partner Physics news on
Scientists uncover clues to role of magnetism in iron-based superconductors
Researchers find first direct evidence of 'spin symmetry' in atoms
X-ray laser probes tiny quantum tornadoes in superfluid droplets