Momentum will be conserved (it always is conserved). If the cars also move at the same speed, and the collision is inelastic, they will both stop completely.
This can happen if they move in opposite directions, and the sum of their momentum is zero. For example, before the collision one may have a momentum of 100 kg x meter / second to the right, and the other 100 kg x meter / second to the left. Thus, their total momentum before the collision would be zero; therefore this would be no problem from this point of view, since the total momentum after the collision is obviously also zero. From the point of view of conservation of energy, mechanical energy is often lost in collisions; most of such energy is converted into heat energy.
It slow down, and eventually reverse direction.
If this happens then they will get pushed apart. Otherwise nothing really will happen unless there is objects at the end were it is pushing.
Sound only happens when there is a collision with another object or a vibration from another object, because that is what a sound is. It can only be soft, loud, strong, weak, light, pitched etc. because it was moved by other existing objects. So sound happens when objects collide or become vibrated.
Two molecules must collide with each other.
This can happen if they move in opposite directions, and the sum of their momentum is zero. For example, before the collision one may have a momentum of 100 kg x meter / second to the right, and the other 100 kg x meter / second to the left. Thus, their total momentum before the collision would be zero; therefore this would be no problem from this point of view, since the total momentum after the collision is obviously also zero. From the point of view of conservation of energy, mechanical energy is often lost in collisions; most of such energy is converted into heat energy.
The season progression would reverse.
It slow down, and eventually reverse direction.
In space and time anything is possible. Within our lifetime, then it will not happen, however in about 2.5 billion years the Andromeda Galaxy will collide with our galaxy, the Milky Way.
They can merge, to combine into a single, larger, galaxy. Or, they can separate again. ------------ "Collide" is a misnomer because of the vast distances between stars in a galaxy, the odds of a stellar collision are extremely small. The Andromeda Galaxy and the Milky Way Galaxy are on a collision course. If you're around when they begin to "collide" in about 4-Billion years, don't expect to see any fireworks in the sky. Except for an increase of the number of observable stars in the night sky, it will largely be a non-event.
AAA When Worlds Collide happened on November 6th, 1994.
a fault
Collision in Korea happened on 1995-04-28.
Qalyoub train collision happened in 2006.
Ngungumbane train collision happened in 2006.
Mathura train collision happened in 2009.
Venpet-Venoil collision happened in 1977.