N just only gives us a direction it is a unit-less vector- it's only specifying a direction at any point in the curve so when I take a dot product with this, it's going to give us essentially what is the magnitude of F going in the direction of N. So this right over here, when you take the dot, it's essentially a part of the magnitude of F going in N's direction and it's going to have the same exact units as F so the units of this part, you're going to have kilograms per meter second and let me make this very clear-