# Is a collision with an immovable object equal to a head-on collision? [duplicate]

Scenario 1

Two identical and bilaterally symmetrical cars, driven by identical drivers in the exact center of the car and in the same body position, each traveling the same speed, collide exactly head on. (Essentially, eliminate all variables that would cause rotation or interpenetration during the collision).

Scenario 2

One of the above cars hits an immovable wall instead of an oncoming car.

Question

Will each car in these scenarios experience the same forces? For clarity, the cars in scenario 1 have twice the closing speed of the car and wall in scenario 2.

## marked as duplicate by Alfred Centauri, ErikE, Emilio Pisanty, Qmechanic♦Oct 26 '13 at 0:26

Basically the answer is that yes, the two cars colliding at a closing speed of $2v$ is the same as a single car hitting an immovable wall at a speed of $v$. The argument is that the cars involved lose the same amount of kinetic energy, $\frac{1}{2}mv^2$, during both crashes, and this energy can go into bending the cars by the same amount.