▁theorem ). ▁ ▁As ▁a ▁result , ▁an ▁imp ulse ▁may ▁also ▁be ▁regarded ▁as ▁the ▁change ▁in ▁momentum ▁of ▁an ▁object ▁to ▁which ▁a ▁result ant ▁force ▁is ▁applied . ▁The ▁imp ulse ▁may ▁be ▁expressed ▁in ▁a ▁simpler ▁form ▁when ▁the ▁mass ▁is ▁constant : ▁ ▁where ▁F ▁is ▁the ▁result ant ▁force ▁applied , ▁t 1 ▁and ▁t 2 ▁are ▁times ▁when ▁the ▁imp ulse ▁begins ▁and ▁ends , ▁respectively , ▁m ▁is ▁the ▁mass ▁of ▁the ▁object , ▁v 2 ▁is ▁the ▁final ▁velocity ▁of ▁the ▁object ▁at ▁the ▁end ▁of ▁the ▁time ▁interval , ▁and ▁v 1 ▁is ▁the ▁initial ▁velocity ▁of ▁the ▁object ▁when ▁the ▁time ▁interval ▁begins . ▁ ▁Imp ulse ▁has ▁the ▁same ▁units ▁and ▁dimensions ▁ ▁as ▁momentum . ▁In ▁the ▁International ▁System ▁of ▁Units , ▁these ▁are ▁ ▁. ▁In ▁English ▁engineering ▁units , ▁they ▁are ▁ ▁. ▁ ▁The ▁term ▁" imp ulse " ▁is ▁also ▁used ▁to ▁refer ▁to ▁a ▁fast - act ing ▁force ▁or ▁impact . ▁This ▁type ▁of ▁imp ulse ▁is ▁often ▁ideal ized ▁so ▁that ▁the ▁change ▁in ▁momentum ▁produced ▁by ▁the ▁force ▁happens ▁with ▁no ▁change ▁in ▁time . ▁This ▁sort ▁of ▁change ▁is ▁a ▁step ▁change , ▁and ▁is ▁not ▁phys ically ▁possible . ▁However , ▁this ▁is ▁a ▁useful ▁model ▁for ▁computing ▁the ▁effects ▁of ▁ideal ▁coll isions ▁( such ▁as ▁in ▁game ▁physics ▁engines ). ▁ ▁Additionally , ▁in ▁ro cket ry , ▁the ▁term ▁" total ▁imp ulse " ▁is ▁commonly ▁used