
262 Forensic Engineering Fundamentals
e astute observer will have noticed that depending on the direction of the initial and
nal angles of the vehicles, the change in velocity vector may lie in one of the four quad-
rants of a standard Cartesian set of coordinates in the x–y plane. e angle of the velocity
change, ΔA, is therefore dened as follows:
First quadrant: ΔA = a tan θ
Second quadrant: ΔA = 180 − a tan θ
ird quadrant: ΔA = 180 + a tan θ
Fourth quadrant: ΔA = 360 − a tan θ
where θ is the angle of ΔV with respect to the x-axis
Introduction to Energy Methods
e path represented in Figure 9.18 is that of trajectory of a mass m moving arbitra ...