Glossary
Collisions
Interactions where objects come into contact, resulting in an exchange of energy and/or momentum.
Example:
When a baseball bat collides with a baseball, the ball's direction and speed change dramatically.
Conservation of Kinetic Energy
A principle that applies specifically to elastic collisions, where the sum of the kinetic energies of the objects before the collision equals the sum after the collision.
Example:
To solve for the final velocities in an elastic collision, you must apply both conservation of momentum and the Conservation of Kinetic Energy equations.
Conservation of Momentum
A fundamental principle stating that the total momentum of an isolated system remains constant if no external forces act on it.
Example:
During any collision, whether elastic or inelastic, the Conservation of Momentum principle allows us to relate the initial and final velocities of the colliding objects.
Elastic Collisions
Collisions where the total kinetic energy of the system is conserved, meaning no kinetic energy is lost to other forms.
Example:
In a game of pool, two billiard balls elastically collide, bouncing off each other with minimal energy loss.
Elastic Collisions
Collisions where the total kinetic energy of the system is conserved, meaning no kinetic energy is lost or transformed into other forms.
Example:
When a cue ball perfectly strikes another billiard ball, the collision is ideally Elastic Collisions because the total kinetic energy before and after remains the same.
Energy Transformation
The process in inelastic collisions where kinetic energy is converted into other forms of energy, such as heat, sound, or potential energy due to deformation.
Example:
During an inelastic collision between a meteor and Earth, significant energy transformation occurs as kinetic energy becomes heat, sound, and deforms the impact site.
Energy Transformation
The process by which energy changes from one form to another, such as kinetic energy converting into thermal or sound energy during a collision.
Example:
In an inelastic collision, the loud 'thud' you hear is evidence of Energy Transformation from kinetic energy into sound energy.
Inelastic Collisions
Collisions where the total kinetic energy of the system is not conserved; some kinetic energy is transformed into other forms like heat, sound, or deformation.
Example:
When a car inelastically collides with a barrier, the car deforms, and kinetic energy is converted into heat and sound.
Inelastic Collisions
Collisions where some of the total kinetic energy of the system is lost or transformed into other forms of energy, such as heat, sound, or deformation.
Example:
A car crash is a classic example of Inelastic Collisions because kinetic energy is converted into sound, heat, and the energy needed to crumple the car's frame.
Kinetic Energy Conservation
The principle stating that the total kinetic energy of a system remains constant before and after an elastic collision.
Example:
If a bowling ball hits a pin in an elastic collision, the sum of the kinetic energies of the ball and pin before impact equals their sum after impact, demonstrating kinetic energy conservation.
Kinetic Energy Lost
The amount of kinetic energy that is transformed into other forms of energy (like heat or sound) during an inelastic collision.
Example:
After a bullet embeds itself in a block of wood, the Kinetic Energy Lost can be calculated by finding the difference between the initial and final kinetic energies of the system.
Momentum Conservation
The principle that the total momentum of an isolated system remains constant in the absence of external forces, applying to all types of collisions (elastic and inelastic).
Example:
Regardless of whether a collision is elastic or inelastic, the total momentum of the system before the collision will always equal the total momentum after, as long as no external forces act.
Perfectly Inelastic Collisions
A specific type of inelastic collision where the colliding objects stick together and move as a single unit after the impact, resulting in the maximum possible loss of kinetic energy.
Example:
When a bullet embeds itself in a block of wood, it's a perfectly inelastic collision because they move together afterward.
Perfectly Inelastic Collisions
A special type of inelastic collision where the colliding objects stick together and move as a single unit after the impact, resulting in the maximum possible loss of kinetic energy.
Example:
When two lumps of clay collide and merge into one larger lump, it's a Perfectly Inelastic Collisions because they move with a common final velocity.
Total Energy
The sum of all forms of energy within a system (kinetic, potential, thermal, etc.). This quantity is always conserved in any isolated system, even if kinetic energy is not.
Example:
Even in an inelastic collision where kinetic energy decreases, the Total Energy of the system, including heat and sound, remains constant.
Total Kinetic Energy
The sum of the kinetic energies of all objects within a defined system. In elastic collisions, this total remains constant.
Example:
Before a perfectly elastic collision, the Total Kinetic Energy of a system of two carts is 10 Joules; after the collision, it will still be 10 Joules.