|
| 1 | +import math |
| 2 | + |
| 3 | + |
| 4 | +def escape_velocity(mass: float, radius: float) -> float: |
| 5 | + """ |
| 6 | + Calculates the escape velocity needed to break free from a celestial body's |
| 7 | + gravitational field. |
| 8 | +
|
| 9 | + The formula used is: |
| 10 | + v = sqrt(2 * G * M / R) |
| 11 | +
|
| 12 | + where: |
| 13 | + v = escape velocity (m/s) |
| 14 | + G = gravitational constant (6.67430 * 10^-11 m^3 kg^-1 s^-2) |
| 15 | + M = mass of the celestial body (kg) |
| 16 | + R = radius from the center of mass (m) |
| 17 | +
|
| 18 | + Source: |
| 19 | + https://en.wikipedia.org/wiki/Escape_velocity |
| 20 | +
|
| 21 | + Args: |
| 22 | + mass (float): Mass of the celestial body in kilograms. |
| 23 | + radius (float): Radius from the center of mass in meters. |
| 24 | +
|
| 25 | + Returns: |
| 26 | + float: Escape velocity in meters per second, rounded to 3 decimal places. |
| 27 | +
|
| 28 | + Examples: |
| 29 | + >>> escape_velocity(mass=5.972e24, radius=6.371e6) # Earth |
| 30 | + 11185.978 |
| 31 | + >>> escape_velocity(mass=7.348e22, radius=1.737e6) # Moon |
| 32 | + 2376.307 |
| 33 | + >>> escape_velocity(mass=1.898e27, radius=6.9911e7) # Jupiter |
| 34 | + 60199.545 |
| 35 | + >>> escape_velocity(mass=0, radius=1.0) |
| 36 | + 0.0 |
| 37 | + >>> escape_velocity(mass=1.0, radius=0) |
| 38 | + Traceback (most recent call last): |
| 39 | + ... |
| 40 | + ZeroDivisionError: Radius cannot be zero. |
| 41 | + """ |
| 42 | + gravitational_constant = 6.67430e-11 # m^3 kg^-1 s^-2 |
| 43 | + |
| 44 | + if radius == 0: |
| 45 | + raise ZeroDivisionError("Radius cannot be zero.") |
| 46 | + |
| 47 | + velocity = math.sqrt(2 * gravitational_constant * mass / radius) |
| 48 | + return round(velocity, 3) |
| 49 | + |
| 50 | + |
| 51 | +if __name__ == "__main__": |
| 52 | + import doctest |
| 53 | + |
| 54 | + doctest.testmod() |
| 55 | + print("Calculate escape velocity of a celestial body...\n") |
| 56 | + |
| 57 | + try: |
| 58 | + mass = float(input("Enter mass of the celestial body (in kgs): ").strip()) |
| 59 | + radius = float(input("Enter radius from the center of mass (in ms): ").strip()) |
| 60 | + |
| 61 | + velocity = escape_velocity(mass=mass, radius=radius) |
| 62 | + print(f"Escape velocity is {velocity} m/s") |
| 63 | + |
| 64 | + except ValueError: |
| 65 | + print("Invalid input. Please enter valid numeric values.") |
| 66 | + except ZeroDivisionError as e: |
| 67 | + print(e) |
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