#9191 mass energy eqivalence

physics/mass_energy_equivalence.py

@@ -0,0 +1,40 @@
+"""
+Mass-energy equivalence
+Reference: https://en.wikipedia.org/wiki/Mass%E2%80%93energy_equivalence
+
+This file defines a function to calculate energy (in joules) equivalent to a given
+mass (in kilograms) using Einstein's mass-energy equivalence equation E=mc^2,
+where m is mass and c = 299,792,458 m/s is the speed of light in a vacuum.
+
+The function takes a single argument mass(in kg) having datatype float and
+returns the energy(in joule) having datatype float
+"""
+
+SPEED_OF_LIGHT = 299792458
+
+
+def calculate_energy(mass: float) -> float:
+    """
+    get energy equivalent of given mass in joules:
+    >>> calculate_energy(1.2)
+    1.0785062144841811e+17
+    >>> calculate_energy(3.0)
+    2.6962655362104528e+17
+    >>> calculate_energy(5)
+    449377589368408820
+    >>> calculate_energy(-5)
+    Traceback (most recent call last):
+      ...
+        raise TypeError("Mass cannot be negative")
+    TypeError: Mass cannot be negative
+    """
+    if mass < 0:
+        raise TypeError("Mass cannot be negative")
+    energy = mass * SPEED_OF_LIGHT**2
+    return energy
+
+
+if __name__ == "__main__":
+    mass = float(input("Enter mass (in kilograms): "))
+    energy = calculate_energy(mass)
+    print(f"Energy equivalent: {energy} joules")