When a particle with mass m₁ is moving at a certain velocity, it collides with another particle that is at rest and has mass m₂. Upon collision, the two masses become embedded in one another to form a single composite object. The collision process is important in understanding the principles of momentum and energy transfer.

Before the collision, the moving mass has kinetic energy because it is moving. The stationary mass does not have any kinetic energy because it is not moving. After collision, the two masses exert forces on each other and thus momentum is transferred from one to another. By the principle of conservation of momentum, the total momentum of the system before the collision must be equal to the total momentum after the collision.

On the other hand, the combined velocity after embedding will be smaller than that before collision due to the embedding of two masses together. Here again, during a collision, kinetic energy changes partly into heat and sound energies and other forms, thereby causing the system velocity to drop at the collision time, reflecting complex dynamics during an inelastic collision.

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