Angular Impulse: J = integral(tau * dt) = Delta(L) = I*(omega_f - omega_i)
Analogous to linear impulse (integral of force = change in momentum).
Instantaneous Axis of Rotation (IAOR): For rolling, the contact point is the IAOR. About the IAOR:
- v_any_point = omega * (distance from IAOR)
- v_cm = omega * R (recovers the rolling constraint)
- v_top = omega * 2R = 2*v_cm
Using the IAOR simplifies many velocity calculations in rolling problems because you treat the motion as pure rotation about the contact point.