# Coriolis Effect in Sports Many sports involve launching balls into the air. Launched balls are projectiles and will be deflected by a tiny amount due to the Coriolis effect from Earth’s rotation.

Athletes never account for the Coriolis effect, and flat-Earthers use it to “disprove” Earth’s rotation. In reality, the deflection from the Coriolis effect in sports is very tiny. It does not mean the Coriolis effect does not exist.

To calculate the Coriolis effect in sports, we need to obtain three variables: the latitude of the location of the sporting event, the speed of the ball in the air, and the distance it traveled. If these variables are available, we can calculate the magnitude of the Coriolis effect.

First, we need to calculate the Coriolis acceleration from the formula: a = v · (2ω · sin φ), where ω is the rate of Earth’s rotation (7.29e-5 radians/second or 0.00417 degrees/second), φ is the latitude of the event, and v is the speed of the ball in the air.

Second, we need to calculate the time the ball traveled in the air by applying the formula t = d / v, where d is the distance of the ball, and v is the speed of the ball.

Finally, we can calculate the Coriolis displacement using the formula: dc = ½ · a · t², where a is the Coriolis acceleration in the previous step, and t is the time the ball traveled in the air.

## Novak Djokovic Tennis Serve

• Latitude: 40.41° North
• Speed: 219 km/h or 60.83 m/s
• Distance: 24 m
• Time: 24 m / 60.83 m/s = 0.3945 s
• Coriolis acceleration: 2 × 60.83 m/s × 7.29e-05 rad/s × sin(40.41°) = 5.75e-3 m/s²
• Coriolis displacement: ½ × 5.75e-3 m/s² × (0.3945 s)² = 0.45 mm

## Roberto Carlos Football Freekick

• Event: 1997 Tournoi de France
• Latitude: 45.77° North
• Speed: 137 km/h or 38 m/s
• Distance: 35 m
• Time: 35 m / 38 m/s = 0.92 s
• Coriolis acceleration: 2 × 38 m/s × 7.29e-05 rad/s × sin(45.77°) = 3.98e-3 m/s²
• Coriolis displacement: ½ ×3.98e-3m/s² × (0.92 s)² = 1.7 mm

## Tiger Woods Golf Drive

• Event: 2002 Mercedes Champ
• Latitude: 21° North
• Time: 10 s
• Distance: 384 m
• Speed: 384 m / 10 s = 38.4 m/s
• Coriolis acceleration: 2 × 38.4 m/s × 7.29e-05 rad/s × sin(21°) = 2e-3 m/s²
• Coriolis displacement: ½ ×2e-3 m/s² × (10 s)² = 100 mm

## Mike Nugent American Football Field Kick

• Event: NFL, Cincinnati Bengals vs Seattle Seahawks
• Latitude: 39.1° North
• Time: 2 s
• Distance: 38.4 m
• Speed: 38.4 m / 2 s = 19.2 m/s
• Coriolis acceleration: 2 × 19.2 m/s × 7.29e-05 rad/s × sin(39.1°) = 1.77e-3 m/s²
• Coriolis displacement: ½ ×1.77e-3 m/s² × (2 s)² = 3.5 mm