Collision

Dynamics

In physics, collision means the action of bodies striking or coming together (touching). Collisions involve forces (there is a change in velocity). Collisions can be elastic, meaning they conserve energy and momentum, inelastic, meaning they conserve momentum but not energy, or totally inelastic (or plastic), meaning they conserve momentum and the two objects stick together.

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The magnitude of the velocity difference at impact is called the closing speed.

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The field of dynamics is concerned with moving and colliding objects.

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Billiards

In billiards, collisions play an important role. Because the collisions between billiard balls are almost perfectly elastic, and the balls roll on a low-friction surface, their predictable behaviour is often used to illustrate Newton's laws of motion.

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Traffic

In traffic such a collision can be between two vehicles, a vehicle and a person, a vehicle and an object, two persons or a person and an object (and more if an animal is involved). It is an accident or even a disaster. At level crossings sometimes a train collides with a vehicle or person. Due to the speed and weight of a train it needs a long distance to stop, typically longer than the train driver can see ahead. When a train collides with a car this is more likely to be deadly for the people in the car than for those in the train, because the train has more mass and momentum.

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See also

• Car accident

Physics: Physics (from the Greek, φυσικός (phusikos), "natural", and φύσις (phusis), "nature") is the science of the natural world in the broadest sense, dealing with matter and energy and the fundamental forces of nature that govern the interaction...

Touch: :This article concerns physical and human touch. For other meanings, see Touch (disambiguation)....

Velocity: :This article is about velocity in physics. For other meanings, see velocity (disambiguation)....

Collision related Images and Photos (experimental)

Collision Course (DVD)

She-Hulk: Cosmic Collision #1 Cover: She-Hulk

Batman Brave & Bold Kryptonite Collision Figure Battle Pack

Italian Liner Andrea Doria Sinking in Atlantic after Collision with Swedish Ship Stockholm