Given, A×v=B where, B is energy. $ ⇒ \;\; A × v=\;\text " Energy "\; $ Dimensional formula of v,[v]=[LT−1] Dimensional formula of E, [E]=[ML2T−2] Let dimensional formula of quantity A=[MaLbTc] ⇒[MaLbTc][LT−1]=[ML2T−2] ⇒[MaLb+1Tc−1]=[ML2T−2] From the principle of homogeneity, a=1 b+1=2⇒b=1 c−1=−2⇒c=−1 ⇒ Dimensional formula of A=[ML0T−1] =[MLT−1] This is the dimensional formula of momentum.