Penalty Kick: Speed vs. Keeper Reaction
World Cup Physics
An 11-metre shot becomes a race of two clocks — ball travel time vs goalkeeper reaction plus dive. Tune both sides and see when each wins.
What to try
- Aim at 3 m and slow the ball to 18 m/s — even a slow keeper saves it because the ball gives them 0.6+ seconds.
- Aim at 3.4 m at 36 m/s — the ball arrives in ~0.31 s, faster than any human can dive that far.
- Slide reaction time up to 0.45 s to simulate a disguised approach — saves drop dramatically across the board.
How this simulation works
Use the Ball Speed slider to set the kicking velocity (15–40 m/s; record-class strikes near 38). Use the Placement slider to aim laterally — 0 m is dead-centre, ±3.66 m is exactly at the post. Use the Keeper Reaction slider to set how long the keeper waits before moving (0.10–0.50 s) and the Dive Speed slider for how fast they cover ground once moving (3–7 m/s). Press Start to launch. The ball traces a straight line to the goal line; the keeper waits, then dives toward the projected arrival point. The verdict — GOAL, SAVE, or WIDE — is resolved deterministically when the ball crosses the line.