The square of this quantity over the quantity (read slowly) “two times reduced mass times r squared” is added to the gravitational potential to give (-5[1])the effective potential. This quantity divided by mass gives the Kerr parameter in the Kerr metric, which describes black holes for which this quantity (10[1])is nonzero. (10[1])A system with a rotationally symmetric Lagrangian conserves this (10[1])quantity per Noether’s (“NUR-tuhʼs”) theorem. This quantity is the time derivative of net torque. The conservation of (10[1])this quantity can be illustrated by a skater pulling (-5[1])their limbs inward while spinning. For 10 points, name this quantity equal to the cross product of position (10[1])and momentum, the rotational analog of (10[1])linear (10[1])momentum. ■END■