Why Is Momentum Conserved but Not Kinetic Energy in an Inelastic Collision?

[bolbol2054]

why although the equations of momentum and kinetic energy of an object contains the same symbols m and v we note in an inelastic collision that momentum unlike the kinetic energy is conserved

 

[Yuqing]

Momentum will always be conserved because of the symmetry regarding Newton III. But kinetic energy does not need to be conserved because it can easily be transformed into heat, sound, deformation, etc. Note that the total energy still is conserved, just not kinetic energy. Moreover, inelastic collisions are defined by us to be a collision which does not conserve kinetic energy much like perfectly inelastic collisions are defined to be a collision where the final two objects "stick" together resulting in the maximum loss in kinetic energy.

 

[Ali Inam]

The kinetic energy is converted into other forms of energy. It all starts or ends with the motion of the body.

The momentum, whereas, is always there, before collision, after collision.

 

[bolbol2054]

that's now clear thank you

 

[PJC01]

Momentum and kinetic energy are two important concepts in physics that are closely related. Both of these quantities involve the mass and velocity of an object, and they are often used to describe the motion of an object.

The equations for momentum and kinetic energy contain the same symbols, such as mass (m) and velocity (v). However, it is important to note that these two quantities have different properties and behave differently in certain situations.

In an inelastic collision, which is a type of collision where the colliding objects stick together and move as one, we observe that momentum is conserved while kinetic energy is not. This means that the total momentum of the system before and after the collision remains the same, but the total kinetic energy changes.

This can be explained by the fact that momentum is a vector quantity, meaning it has both magnitude and direction. In an inelastic collision, the direction of the total momentum of the system remains the same, even though the objects may have changed their velocity and direction of motion. On the other hand, kinetic energy is a scalar quantity, meaning it only has magnitude. In an inelastic collision, some kinetic energy may be converted into other forms of energy, such as heat or sound, resulting in a decrease in the overall kinetic energy of the system.

Therefore, although the equations of momentum and kinetic energy contain the same symbols, they represent different physical quantities and behave differently in certain situations. Understanding the differences between these two quantities is crucial in accurately describing and analyzing the motion of objects.