calculate_projectile_with_drag
Calculate realistic projectile trajectories by modeling air resistance, spin effects, wind, and altitude-based air density changes for sports balls and other objects.
Instructions
Calculate projectile motion including air resistance (drag).
Uses numerical integration (RK4) to solve motion equations with:
- Quadratic drag force: F_drag = 0.5 * ρ * v² * Cd * A
- Magnus force (spin effects): F_magnus = 0.5 * ρ * Cl * A * ω * r * v
- Wind effects (constant wind vector)
- Variable air density (altitude and temperature effects)
This provides REALISTIC trajectories for sports balls, projectiles,
and other objects moving through air or water. Compare with
calculate_projectile_motion (no drag) to see dramatic differences!
Common drag coefficients (Cd):
- Sphere: 0.47 (default)
- Baseball: 0.4
- Golf ball: 0.25 (dimples reduce drag)
- Football (American): 0.05-0.15 (orientation-dependent)
- Basketball: 0.55
- Soccer ball: 0.25
- Skydiver (belly-down): 1.0-1.3
- Streamlined car: 0.25-0.35
Args:
initial_velocity: Launch velocity in m/s
angle_degrees: Launch angle in degrees (0-90)
mass: Object mass in kg
cross_sectional_area: Cross-section perpendicular to motion in m²
initial_height: Launch height in meters (default 0)
drag_coefficient: Drag coefficient Cd (default 0.47 for sphere)
fluid_density: Fluid density in kg/m³ (air=1.225, water=1000)
gravity: Gravitational acceleration m/s² (default 9.81)
time_step: Integration time step in seconds (default 0.01)
max_time: Maximum simulation time in seconds (default 30)
spin_rate: Spin rate in rad/s for Magnus force (default 0, no spin)
spin_axis: Spin axis unit vector [x, y, z] (default [0, 0, 1] = vertical)
wind_velocity: Wind velocity [vx, vy] in m/s (default [0, 0], no wind)
altitude: Altitude above sea level in meters (default 0, affects air density)
temperature: Air temperature in Celsius (default 15, affects air density)
Returns:
Dict containing:
- max_height: Maximum altitude reached (m)
- range: Horizontal distance traveled (m)
- time_of_flight: Total flight time (s)
- impact_velocity: Speed at landing (m/s)
- impact_angle: Angle at landing (degrees below horizontal)
- trajectory_points: [[x, y], ...] for plotting
- energy_lost_to_drag: Energy dissipated by drag (J)
- initial_kinetic_energy: Initial KE (J)
- final_kinetic_energy: Final KE (J)
- lateral_deflection: Lateral deflection from spin/wind (m)
- magnus_force_max: Maximum Magnus force magnitude (N)
- wind_drift: Total wind drift (m)
- effective_air_density: Effective air density used (kg/m³)
Example - Baseball curveball (2500 rpm backspin):
result = await calculate_projectile_with_drag(
initial_velocity=40.23, # 90 mph
angle_degrees=10,
mass=0.145,
cross_sectional_area=0.0043,
drag_coefficient=0.4,
spin_rate=261.8, # 2500 rpm = 261.8 rad/s
spin_axis=[0, 0, 1] # Backspin (vertical axis)
)
# Backspin increases range and height!
Example - Golf ball at altitude (Denver, 1600m):
result = await calculate_projectile_with_drag(
initial_velocity=70,
angle_degrees=12,
mass=0.0459,
cross_sectional_area=0.00143,
drag_coefficient=0.25,
altitude=1600, # Denver elevation
temperature=20 # Summer day
)
# Less air resistance = longer drive!
Example - Soccer free kick with wind:
result = await calculate_projectile_with_drag(
initial_velocity=25,
angle_degrees=15,
mass=0.43,
cross_sectional_area=0.0388,
drag_coefficient=0.25,
wind_velocity=[5, 0], # 5 m/s tailwind
spin_rate=50, # Sidespin for curve
spin_axis=[0, 1, 0] # Horizontal axis
)
# Wind drift + Magnus curve!
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| initial_velocity | Yes | ||
| angle_degrees | Yes | ||
| mass | Yes | ||
| cross_sectional_area | Yes | ||
| initial_height | No | ||
| drag_coefficient | No | ||
| fluid_density | No | ||
| gravity | No | ||
| time_step | No | ||
| max_time | No | ||
| spin_rate | No | ||
| spin_axis | No | [0, 0, 1] | |
| wind_velocity | No | [0, 0] | |
| altitude | No | ||
| temperature | No |