I=50м S=1мм² v=45R I-?

To find the current (I) in your context, we need additional information. However, it appears that you have provided the length (I = 50 m), cross-sectional area (S = 1 mm²), and a velocity (v = 45 R), which might not directly relate, depending on the context.

If you are dealing with electrical properties and Ohm's law or similar concepts, please clarify if you are looking for information related to resistivity, current density, or any specific situation involving electrical circuits or fluid dynamics.

For example:

1. If you are calculating current based on resistivity: \[ I = \frac{V}{R} \]
2. If you are calculating current density: \[ J = \frac{I}{A} \]

Please provide more information or clarify the physical situation you are dealing with!