# If a non-unit-speed has constant curvature and zero torsion, is it a circle necessarily?

But in that answer, we assume that the curve at hand has unit speed. In working with the cross-sectional curve of a circular helix, I do not know my curve has unit speed. How can I still show that the cross-sectional curve is a circle? I have demonstrated that it has constant curvature, lies in a plane and has zero torsion.

• Why not reparameterize it so that it has unit speed? – MSobak Jul 21 '18 at 7:47
• A circular helix is a curve, and its cross section is a point !? – Yves Daoust Jul 21 '18 at 7:51