MomentumInLine app for iPhone and iPad

The Momentum In-Line application is designed to determine vehicle speeds of vehicles involved in “in-line” type collisions. The program utilizes the conservation of linear momentum in order to determine velocities.

In order to determine the speeds of the involved vehicles the weights (masses) of both vehicles is entered along with three of the four speeds (two post impact speeds and two impact speeds). When any 3 speeds are known the 4th may be calculated. Therefore, the investigator is not limited to determining just the impact speed of Vehicle #1, as is the case with may traditional momentum applications. Instead, they may calculate the impact speed of Vehicle #2 or the post impact speed of either vehicle.

The program utilizes a series of arrows to determine the relative direction of the involved vehicles. The investigator simply needs to touch the arrow adjacent to the entered or calculated speed in order to set the vehicle’s relative direction.

In addition to the ability to directly enter the various speeds and vehicle weights, the entered values may be adjusted through the use of a slider. As the related slider is moved from side-to-side, its value changes along with the calculation results. This permits the investigator to instantly check the sensitivity of their raw data to the related calculations.

The second page displays the momentum calculations in a step-by-step fashion. In addition, it displays the results in a fps or m/s format along with the closing velocity, separation velocity and collision restitution.