Hello, I have a project for my diploma.And i have some questions. If someone can help me i would be very pleased. I have to know what the cables resistance ( σ ( N/mm2)) is,i mean, how big a force, do i need for cut the cable's plastic?I have a disc (it should be the knife), when it turns around it, it should cut the plastic-all the cover; and the copper should appear. I thought like this ; σ = F / A and if i know σ, i could find the force, and from force to momentum and then the engines HP .. Did i thing exact? Thanks..