If you plotted the original path and velocity, and the path and velocity of the 'impacting' force, then the third leg of the triangle will be the resultant path and velocity.
A unit vector has a length (magnitude) equal to 1 (one unit). A rectangular vector is a coordinate vector specified by components that define a rectangle (or rectangular prism in three dimensions, and similar shapes in greater dimensions). The starting point and terminal point of the vector lie at opposite ends of the rectangle (or prism, etc.).
a vector with nothing in it
A resultant vector is one vector which can replace all the other vectors and produce the same effect.
It is a vector that has the opposite direction to the reference positive direction. (A vector is one point in space relative to another.) Negative vector is the opposite direction
It is a measure which has a direction as well as a value.
i had 2 change what i thought
It stands for gradient vector flow.
The 'orthcentre' of a triangle is at the point where the 3 perpendicular altitudes intersect within the triangle.
If you meant right angle then yes
The dimensions of a rectangular plot are its length and width.
Normal to the surface is a vector which is perpendicular to that surface
Velocity is a vector. As every vector in includes direction and magnitude (as 'oppose' to scalar). If that is what you meant by this vague question.