A generalization of this law to quantum mechanical operators is known as the Ehrenfest Theorem, while in non-inertial reference frames it holds only for effective force unless one adds terms to the right side for centrifugal, coriolis, and (*) azimuthal forces. When mass is not constant, this law is often given as "impulse equals the integral of force with respect to time," or that F equals dp dt. For 10 points, identify this law of classical mechanics which states that 
A generalization of this law to quantum mechanical operators is known as the Ehrenfest Theorem, while in non-inertial reference frames it holds only for effective force unless one adds terms to the right side for centrifugal, coriolis, and (*) azimuthal forces. When mass is not constant, this law is often given as "impulse equals the integral of force with respect to time," or that F equals dp dt. For 10 points, identify this law of classical mechanics which states that force equals mass times acceleration.
A generalization of this law to quantum mechanical operators is known as the Ehrenfest Theorem, while in non-inertial reference frames it holds only for effective force unless one adds terms to the right side for centrifugal, coriolis, and (*) azimuthal forces.
Newton's Second Law [prompt on Newton's Law]