Sudden and large change of motion of a body by force acting for a very short duration is called collision. When two objects hit into each other, this is called a collision. Striking a cricket ball by a bat, striking a carom globule by a striker, firing a bullet from a gun etc are examples of a collision. When an alpha panic approaches a gold nucleus then they repel each other with a high speed for a very short tutee. This event is called collision. Collisions are of two types;
Examples: One ball striking another on a pool table; A baseball bat hitting a ball etc.