Task: Text Categorization
Input (English): One equation for discovering this value multiplies the masses of two objects over the radius squared multiplied by this force's universal constant. When this weakest of the four fundamental forces is equal to the drag force on an object, that object will be at a terminal velocity. An object's weight is equal to mass multiplied by this force. For 10 points, name this force that acts as a downward acceleration on an object on Earth at 9.8 meters per second squared, which was studied by Isaac Newton possibly because of an apple.
Output (English): Science