Editing Lap time and delta analysis (section)

== Physics back-bone (friction ellipse & power) ==

Friction-ellipse constraint (per tyre) maps combined usage:
<math>
\left(\frac{F_{x}}{\mu F_z}\right)^2 + \left(\frac{F_{y}}{\mu F_z}\right)^2 \;\le\; 1,
</math>
so braking deep (high <math>F_x</math>) reduces available lateral <math>F_y</math> and sets the attainable entry/rotation trade-off. Longitudinal acceleration is power-limited at high speed:
<math>
a_x \approx \frac{P_{\mathrm{drv}}}{m \, v} \;-\; \frac{D(v)}{m},
\qquad
D(v)=\tfrac{1}{2}\rho C_D A v^2,
</math>
governing straight-line delta growth when one lap has higher deployment or lower drag.