Task: Text Categorization
Input (English): This quantity is equal to the cross product of dipole moment and electric field, and an epicyclic mechanism including "sun" and "planet" gears "multiply" it. Varignon proved that this is additive when applied at the same point. Power is the scalar product of this quantity and omega, or angular velocity. Work is the integral of this quantity with respect to theta, and a lever in rotational equilibrium has a net value of zero for this quantity. This quantity can be measured by newton-meters or joules per radian, and is denoted by the letter tau. For 10 points, name this time derivative of angular momentum and rotational analogue of force, which is the cross product of lever arm and force.
Output (English): Science