Is angular impulse always equal to the change of angular momentum in collisions between rigid bodies?

The relationships between angular impulse and angular momentum have been derived in the particular case of collisions between rigid bodies. It is shown that the change in absolute angular momentum about an arbitrary reference point is always equal to the angular impulse. However, the change in relative angular momentum is equal to the angular impulse only when it is calculated about particular points. We illustrate with two examples the differences between both equations. Laburpena: Bultzada angeluarraren eta momentu angeluarraren arteko erlazioak partikularizatuta solido zurrunaren talken kasurako aztertu dira. Momentu angeluar absolutoaren aldaketa edozein puntutan kalkulatuta beti dela bultzada angeluarra frogatzen da. Baina momentu angeluar erlatiboaren aldaketa da bultzada angeluarra puntu berezietan kalkulatzen bada. Ekuazioen arteko ezberdintasunak bi adibideren laguntzarekin erakusten ditugu.