# What Causes Kinetic Energy To Not Be Conserved

• MaZnFLiP
In summary, a lab was conducted to investigate the conservation of kinetic energy during collisions. However, data showed that kinetic energy was not conserved in any of the trials. The question arose as to why this was the case, and it was found that the friction force from the velcro used to stick the cars together was the cause. This friction force converted the kinetic energy into heat energy, which was not accounted for in the calculations. Thank you.
MaZnFLiP
[SOLVED] What Causes Kinetic Energy To Not Be Conserved

## Homework Statement

In class today we did a lab that dealt with a question about Kinetic Energy. I thought that Kinetic Energy would always be conserved but when we collected our data, that was not the case. According to the data we received, not a single trial we did showed that the Kinetic Energy was conserved. So this brings me up to my question. In the Questions portion of the lab, it is asking the reason as to why the Kinetic Energy isn't conserved if that is what we solved for. What we did was we hit cars together on a frictionless track where they would go in a straight line. We also did a total of 24 trials (12 Elastic crashes and 12 Inelastic Crashes)

## Homework Equations

KEi = KEf + Ff + X?

## The Attempt at a Solution

What I was thinking is that it has to be friction force that was causing this since not all tracks can be completely frictionless. But even if friction force were to be a part of it, it would have minimal impact on the two colliding objects. When I calculated, the Friction Force number just seemed way to large to be the cause of something like this. I looked on other sites and it says Kinetic Energy can be turned into Heat Energy or other various types of Energies but we haven't learned anything about any other types of energies except for Potential and Kinetic Energy. Is there possibly something I missed? Or is it actually Heat energy that is causing this?

If you are sticking the cars together with velcro, that's a huge friction source. That's what it's for. And, yes, the KE it soaks up goes into heat. You don't notice the heat because it takes quite a bit of mechanical energy to create a noticeable amount of heat. Try and create fire by rubbing two sticks together.

Oh!

Oh okay. Yeah they did stick together with velcro. Okay that makes sense then. Thanks so much!

## 1. What is kinetic energy and why is it important?

Kinetic energy is the energy that an object possesses due to its motion. It is important because it is a fundamental concept in physics and is useful in understanding the behavior and properties of moving objects.

## 2. How is kinetic energy typically conserved?

In an isolated system, where there are no external forces acting on the object, kinetic energy is typically conserved. This means that the total amount of kinetic energy in the system remains constant and does not change.

## 3. What are some factors that can cause kinetic energy to not be conserved?

One factor that can cause kinetic energy to not be conserved is the presence of external forces, such as friction or air resistance, which can slow down an object and convert its kinetic energy into other forms of energy. Inelastic collisions, where some of the kinetic energy is lost in the form of heat or sound, can also cause a decrease in the overall kinetic energy of a system.

## 4. How does the law of conservation of energy relate to kinetic energy?

The law of conservation of energy states that energy cannot be created or destroyed, only transferred or converted from one form to another. This means that while kinetic energy may not be conserved in a specific situation, the total amount of energy in the system must remain constant.

## 5. Can kinetic energy ever be completely conserved?

In theory, yes, kinetic energy can be completely conserved in an isolated system with no external forces acting on it. However, in the real world, it is nearly impossible for all external forces to be eliminated, so some amount of kinetic energy will always be lost or converted into other forms of energy.

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