Given in my book- 1."Velocity Of approach - It is the rate at which distance between two moving particle decreases. V(Approach) =V1cosα + V2cosβ " 2."When the distance between two particles is minimum, the relative veloctiy of approcah is 0" 3."V1cosα + V2cosβ = 0 .....when distance is minimum(diagram in attachment below)" Please Explain Why? And, the above equation will become 0 only if cosα = 0 and cosβ = 0 at same time, but if α and β are not equal, then cosα and cosβ cannot be 0 at same time. Thus the Equation is worng but giving correct answers. Please Explain Why?