# Calculate the torque on a rigid body

1. Apr 11, 2004

### DNA

Can someone please tell me if it is possible to calculate the torque on a rigid body without specifying the origin?

2. Apr 11, 2004

### jjgallag

if you think about it a torque vector is oriented in the 3D-Euclidian space. the point of orientation is relative to some orgin in a chosen coordinate system. Now if you take the coordinate system away then you just have the vector part of the torque. this would imply that the direction and magnitude of the torque would be assumed and not computed, because the torque equation doesn't allow it to calculated without the origin specified(i.e. transformations from manifold-to-maniflold can occur). therefore, the torque cannot be computed without an origin, because it would cease to exist as a torque vector.this might not seem so obvious, but try the following problem and take away the origin from your coordinate system and try the same problem with the origin in the coordinate system(hint: use spherical coordinates). think about the torgue developed by the rotation of the Earth go through the calculation. keeping what I previously said in mind one should realize the validity of this rationalization.

3. Apr 11, 2004

### DNA

I think that i understand, manifold to manifold transformations,spherical coordinates! I am only beginning my physics journey, it would seem that i have a long way to go.