When tearing a sheet of paper most people exert a force perpendicular to the sheet, rather than grabbing the sheet by the edges and trying to pull it apart. The physics of this can be understood with a simple model.

Consider a row of three springs along the x-axis with the same spring constant and length, connected end to end. Initially, they are all at their natural length. If any of them stretch by more than one percent they will break. This is our paper.
**$F/N$** when the middle spring breaks.

**Details and assumptions**

- Hint 1: Do NOT assume that the ends of the springs move only vertically.
- Hint 2: tear the paper slowly and think about force balances.