energy_mass_equivalent.py

import scipy.constants as const
import math


def energy_equivalent_for_stationary_mass(mass_kg):
    """
    Calculate the energy equivalent for a given mass using E=mc^2.

    Parameters:
        mass_kg (float): Mass in kilograms.(must be positive)

    Returns:
        float: Energy equivalent in joules.

    >>>energy_equivalent_for_stationary_mass(4)                 
    3.5950207149472704e+17

    """
    if mass_kg<0:
        ValueError("mass of object cannot be negative")
      
    speed_of_light = const.speed_of_light  # Speed of light in meters/second
    energy_joules = mass_kg * (speed_of_light ** 2)
    return energy_joules


def energy_equivalent_for_moving_mass(mass_kg, velocity_m_s):
    """
    Calculate the energy equivalent for a moving mass using relativistic energy-momentum relation(E^2= m^2*c^4 +p^2*c^2).

    Parameters:
        mass_kg (float): Mass in kilograms.(must be positive)
        velocity_m_s (float): Velocity in meters per second.(can be negative as well as positive)

    Returns:
        float: Energy equivalent in joules.

    >>>energy_equivalent_for_moving_mass(1,5675)       
    1701322225868.2546
    """
    if mass_kg<0:
        ValueError("mass of object cannot be negative")
        
    speed_of_light = const.speed_of_light  # Speed of light in meters/second

    # Calculating momentum
    momentum = mass_kg * velocity_m_s / math.sqrt(1 - (velocity_m_s**2 / speed_of_light**2))

    # Calculating energy using the relativistic energy-momentum relation
    energy_joules = math.sqrt((mass_kg * speed_of_light)**2 + (momentum * speed_of_light)**2)
    return energy_joules

if __name__ == "__main__":
    import doctest
    doctest.testmod()