Magnus Effect Free Kick
World Cup Physics
Curl a free kick around a wall — Magnus force perpendicular to velocity, plus quadratic drag. Top-down half-pitch with goal at 30 m.
What to try
- Set spin to 0 — the trajectory is essentially a straight line modulated by drag.
- Aim 12° wide right and apply +12 rev/s of spin — the ball leaves outside the wall and curls back into the far post.
- Hold spin and lift constant; sweep speed from 22 to 34 — faster shots curl less because they spend less time in the air.
How this simulation works
Use the Ball Speed slider to set how fast the ball leaves the boot (20–35 m/s). Use the Spin Rate slider to set the angular spin about a vertical axis (−15 to +15 rev/s; positive is counter-clockwise from above and curls the ball toward the upper side of the canvas). Use the Heading Offset slider to point the kick left or right of the straight line to goal. Use the Lift Coefficient slider to scale how aggressively spin converts into lateral force (0.15–0.35). Press Start and watch the path bend; the readouts show lateral deflection at the goal line, peak curve, and time to goal.