Find the principle unit normal vector to the curve given below at the specified point: r(t) = 4cos(t) i + 4 sin(t) j, t=pi/6<BR><BR>I think it's the dot product of something, can't find it in my book.

In this problem, we know both the magnitude and direction for each of the velocity and acceleration vectors for the center of mass G. We know that the unit tangent vector e t is in the same direction ...