# Elastic collision

## Formula

General : Define recovery coefficient E = (V ' 2 -v' 1 1 >) / (V 1 -v 2 ), if only the altitude collision is considered, the relative speed is opposite to each other because there is a relative speed before the collision collision, there is V ' 2 -v ' 1 = - E (V 1 -v 2 ) (1)

Using the definition of zero and relative speed using a degree of magistrate, it is easy to introduce a speed expression after collision in a cuspcle. Finally, it is easy to get a collision speed after the expression in the expression:

Take E = 1 to obtain a speed expression after complete elastic collision.

Using the recovery factor E = (V ' 2 -v' 1 ) / (v 1 < / sub> -v 2 ) and momentum conservation law can derive the speed formula after the elastic collision:

If the recovery coefficient is equal to 1, there is a formula:

Motorcycle Conservation Law Formula:

Putting two formulas to solve the equation:

< P>

or, regressing high school physics : Set two object quality

, Collision Speed ​​
. For complete flexible collisions: two objects collision speed
can be simply exported by momentum conservation and energy conservation law:

momentum conservation:

Energy Conservation Law:

Two objects collision speed:

Note: Speed ​​

is vector.

## Properties

The following formula can be obtained as the following properties:

1. (only the core collision)

: two objects Before the collision, the relative speed is equal to the opposite direction.

2. Total momentum

and total energy
unchanged: The vector and energy of the momentum are unchanged before and after the two objects collide.

3. If

is equal,
and
: If the two objects are the same, the speed size direction is interchanged.

## Other

The type of collision is also: completely elastic collision, non-elastic collision, completely non-elastic collision.

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