Colliding Cars

Initializing live version
Download to Desktop

Requires a Wolfram Notebook System

Interact on desktop, mobile and cloud with the free Wolfram Player or other Wolfram Language products.

Two cars collide at an intersection as shown in the figure. They have masses and and velocities and ; is time. Assume that the collision is perfectly inelastic in two dimensions—the two objects stick together with a great deal of kinetic energy lost. The final velocity and the angle that the cars follow when they move off after the crash are calculated using the law of conservation of momentum.

Contributed by: Enrique Zeleny (March 2011)
Open content licensed under CC BY-NC-SA



The expressions for the angle and final velocity are



At 100 km/hr (equivalent to 27.8 m/s), a car traveling for 0.75 seconds moves almost 21 meters; the length of the car is taken as 3.3 m.

Further details that are important in real crashes, such as reaction time, braking, friction, center of mass, etc., are ignored in this Demonstration.

Feedback (field required)
Email (field required) Name
Occupation Organization
Note: Your message & contact information may be shared with the author of any specific Demonstration for which you give feedback.