CP-Momentum

CP-Momentum is a 360° Linear Momentum Application. However, unlike any other 360° momentum application or computer program, it takes a different approach when determining speeds.

Often the crash investigator is presented with cases where the post impact speeds of the involved vehicles cannot be determined. However, there is sufficient information to determine each vehicle’s approach and departure angles, and the damage profiles of the vehicles are such that, it is known that their post impact speeds are similar, if not the same. This is the situation that the CP-Momentum Application was designed to address.

Like all 360° momentum programs, the application works with approach and departure angles or headings and vehicle weights/masses, at this point the similarities end. The CP-Momentum Application (Common Post Impact Speed Relationship) works with a single impact speed that the user enters, and a relationship between the post impact speeds, established by the user through the use of the slider.

Once the vehicle weights/masses, angles and impact speed have been entered the application will calculate both post impact speeds as well as the second vehicle’s impact speed. The initial calculations assume the post impact speeds of both vehicles are the same. This assumption may be changed by the user simply by adjusting the post impact speed slider, which allows the post impact speeds to range from Vehicle #1’s being 100% greater than Vehicle #2’s to Vehicle #2’s being 100% greater than Vehicle #1’s. Ironically, even though this allows for a 200% variance in the post impact speeds, it often has a minimal influence on the calculated impact speed. Thereby, providing the investigator with a useful range of impact and post impact speeds, even when they can’t be determined through traditional methods.

In addition to calculating the impact and post impact speeds, the application determines the change in velocity for each vehicle as well as their respective PDOFs.

On a separate screen the velocities are displayed in units of fps-m/s along with the impact and post impact kinetic energy of each vehicle, their respective change in direction, their closing and separation velocity as well as the collision restitution.

A third screen displays the momentum, pdof and ∆v calculations in a step-by-step fashion.

The momentum, pdof and ∆v results, with the math worked in a line-by-line manner may be emailed, permitting the user to copy and paste the calculations into another document or report.

The application works in both Imperial or Metric units while converting all values (including entered data) between the two units of measurements.