Add algorithm for Newton's Law of Gravitation

physics/newtons_law_of_gravitation.py

@@ -0,0 +1,100 @@
+"""
+Title : Finding the value of either Gravitational Force, one of the masses or distance
+provided that the other three parameters are given.
+
+Description : Newton's Law of Universal Gravitation explains the presence of force of
+attraction between bodies having a definite mass situated at a distance.  It is usually
+stated as that, every particle attracts every other particle in the universe with a
+force that is directly proportional to the product of their masses and inversely
+proportional to the square of the distance between their centers. The publication of the
+theory has become known as the "first great unification", as it marked the unification
+of the previously described phenomena of gravity on Earth with known astronomical
+behaviors.
+
+The equation for the universal gravitation is as follows:
+F = (G * mass_1 * mass_2) / (distance)^2
+
+Source :
+- https://en.wikipedia.org/wiki/Newton%27s_law_of_universal_gravitation
+- Newton (1687) "Philosophiæ Naturalis Principia Mathematica"
+"""
+
+from __future__ import annotations
+
+# Define the Gravitational Constant G and the function
+GRAVITATIONAL_CONSTANT = 6.6743e-11  # unit of G : m^3 * kg^-1 * s^-2
+
+
+def gravitational_law(
+    force: float, mass_1: float, mass_2: float, distance: float
+) -> dict[str, float]:
+
+    """
+    Input Parameters
+    ----------------
+    force : magnitude in Newtons
+
+    mass_1 : mass in Kilograms
+
+    mass_2 : mass in Kilograms
+
+    distance : distance in Meters
+
+    Returns
+    -------
+    result : dict name, value pair of the parameter having Zero as it's value
+
+    Returns the value of one of the parameters specified as 0, provided the values of
+    other parameters are given.
+    >>> gravitational_law(force=0, mass_1=5, mass_2=10, distance=20)
+    {'force': 8.342875e-12}
+
+    >>> gravitational_law(force=7367.382, mass_1=0, mass_2=74, distance=3048)
+    {'mass_1': 1.385816317292268e+19}
+
+    >>> gravitational_law(force=36337.283, mass_1=0, mass_2=0, distance=35584)
+    Traceback (most recent call last):
+        ...
+    ValueError: One and only one argument must be 0
+
+    >>> gravitational_law(force=36337.283, mass_1=-674, mass_2=0, distance=35584)
+    Traceback (most recent call last):
+        ...
+    ValueError: Mass can not be negative
+
+    >>> gravitational_law(force=-847938e12, mass_1=674, mass_2=0, distance=9374)
+    Traceback (most recent call last):
+        ...
+    ValueError: Gravitational force can not be negative
+    """
+
+    product_of_mass = mass_1 * mass_2
+
+    if (force, mass_1, mass_2, distance).count(0) != 1:
+        raise ValueError("One and only one argument must be 0")
+    if force < 0:
+        raise ValueError("Gravitational force can not be negative")
+    if distance < 0:
+        raise ValueError("Distance can not be negative")
+    if mass_1 < 0 or mass_2 < 0:
+        raise ValueError("Mass can not be negative")
+    if force == 0:
+        force = GRAVITATIONAL_CONSTANT * product_of_mass / (distance**2)
+        return {"force": force}
+    elif mass_1 == 0:
+        mass_1 = (force) * (distance**2) / (GRAVITATIONAL_CONSTANT * mass_2)
+        return {"mass_1": mass_1}
+    elif mass_2 == 0:
+        mass_2 = (force) * (distance**2) / (GRAVITATIONAL_CONSTANT * mass_1)
+        return {"mass_2": mass_2}
+    elif distance == 0:
+        distance = (GRAVITATIONAL_CONSTANT * product_of_mass / (force)) ** 0.5
+        return {"distance": distance}
+    raise ValueError("One and only one argument must be 0")
+
+
+# Run doctest
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()