These calculations are for angled collisions, where the speeds of both vehicles are unknown and where the angle of approach is greater than about 20 degrees.
This calculator should NOT be used where the pre-impact vehicle directions are within 20 degrees of being in line.
Draw a sketch, like the one shown below, showing the pre-impact and post-impact directions of each vehicle.
Align the initial direction of the lighter vehicle (1) with the Y-axis (i.e. 0 degrees).
Measure all angles clockwise from the direction of travel of vehicle 1.
You can use any units of speed, but the units of speed MUST be the same units for both vehicles. Do NOT use different units of speed for vehicle 1 and 2 (e.g. do NOT use m/s for vehicle 1 and then MPH for vehicle 2 but instead use m/s for both or MPH for both).
Fill in all of the 8 boxes below and click on the Calculate button to display the pre-impact speeds of both vehicles.
The output will be in the speed units of speed that you used for the input. For example, if you chose to use use KMH for the post-impact speeds then the output will be in KMH also.
Vehicle 1 mass (kg): m1 =
Vehicle 1 pre-impact direction (degrees): (Vehicle 1 is always aligned to 0 degrees)
Vehicle 1 post-impact direction (degrees): Ø'1 =
Vehicle 1 post-impact speed: v1 =
Vehicle 2 mass (kg): m2 =
Vehicle 2 pre-impact direction (degrees): Ø2 =
Vehicle 2 post-impact direction (degrees): Ø'2 =
Vehicle 2 post-impact speed: v2 =
Vehicle 1 pre-impact speed: u1 =
Vehicle 2 pre-impact speed: u2 =
Back to main calculator menu.