Task: Text Categorization
Input (English): This quantity for an atomic nucleus is determined using Weizscker's [VAHYTS-zek-uhrs] formula. The no hair theorem states black holes are completely characterized by their angular momentum, charge, and this quantity. The oscillation period of a spring equals two pi times the square root of this quantity over the spring constant. The theoretical value of this quantity for gluons is zero. Linear momentum equals this quantity times velocity. For 10 points, name this quantity measured in kilograms.
Output (English): Science