# Conservation of Kinetic Energy During Collision

• mohabitar
In summary, The conversation discusses the use of the equation K=1/2MV^2 in solving a problem. The speaker tried using the equation but it did not work. They then asked for ideas on how to approach the problem and it was suggested to calculate the initial and final kinetic energy. The speaker realized their mistake and asked why the final energy should be subtracted from the initial energy. The response was that change always means final minus initial, and if the change is positive, then energy has been gained.
mohabitar

For number 3, I don't really know how to approach it. Nothing in my notes that covers such a thing. I tried using K=1/2MV^2, but that's not it. Any ideas?

mohabitar said:
I tried using K=1/2MV^2, but that's not it. Any ideas?
What do you mean "that's not it"? Did you calculate the initial and final kinetic energy?

Ohh, duh! So subtract the final kinetic from initial kinetic. Well actually it turned out that we subtract initial from final, why do we do that rather than final from initial? (how do we know whether it lost or gained energy)

Change always means final minus initial. If the change is positive, then you've gained energy. (Is that likely?)

Hello,

Thank you for your question. Conservation of kinetic energy during a collision is a fundamental principle in physics. It states that the total kinetic energy of a system before and after a collision remains constant. This principle is based on the law of conservation of energy, which states that energy cannot be created or destroyed, only transferred from one form to another.

To approach number 3, you can use the equation for conservation of kinetic energy, which is:

KE1 + KE2 = KE3

Where KE1 is the initial kinetic energy of the system, KE2 is the kinetic energy of the object in motion, and KE3 is the final kinetic energy of the system after the collision.

In this equation, KE1 and KE2 are known values, as they can be calculated using the equation you mentioned, K=1/2MV^2. KE3 is the unknown value that you need to solve for. You can rearrange the equation to solve for KE3, which will give you the final kinetic energy of the system after the collision.

I hope this helps. If you have any further questions, please let me know.

Best,

## 1. What is the principle of conservation of kinetic energy during collision?

The principle of conservation of kinetic energy during collision states that the total amount of kinetic energy in a closed system before and after a collision remains constant. This means that the total kinetic energy of the objects involved in the collision does not change, but rather is transferred between the objects.

## 2. How is the conservation of kinetic energy applied in real-life situations?

The conservation of kinetic energy is applied in various real-life situations, such as in car crashes. The kinetic energy of a moving car is transferred to other objects, such as the other car involved in the collision or the airbags, during a collision. This principle also applies in sports, such as billiards, where the energy of a moving cue ball is transferred to the other balls upon collision.

## 3. What factors affect the conservation of kinetic energy during collision?

The conservation of kinetic energy during collision is affected by various factors, including the mass, velocity, and direction of the objects involved in the collision. The type of materials and the presence of external forces, such as friction, can also affect the transfer of kinetic energy.

## 4. Can the conservation of kinetic energy be violated?

No, the conservation of kinetic energy is a fundamental law of physics and cannot be violated. However, in some situations, it may appear that kinetic energy is not conserved due to external factors, such as heat or sound energy being produced during a collision.

## 5. How does the conservation of kinetic energy relate to other laws of physics?

The conservation of kinetic energy is closely related to other laws of physics, such as the law of conservation of energy and the law of conservation of momentum. These laws all describe the transfer and transformation of energy in a closed system, and they are all fundamental principles in understanding the behavior of objects in motion.

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