# Collision Conservation of Energy

• jakeginobi
In summary, the conversation discusses a scenario where a 5.0 x 10^5kg railroad car moving at 8.0m/s collides with a stationary railroad car of equal mass. After the collision, the two cars lock together and slide forward. The question posed is what is the final velocity of the wrecked cars. The attempt at a solution involves using conservation of energy, with the equation Ek = 1/2mv^2. The type of collision is identified as an elastic collision, where conservation of energy and momentum are both conserved. However, it is noted that the teacher had not yet covered collision questions using conservation of energy.
jakeginobi

## Homework Statement

a 5.0 x 10^5kg railroad car moving at 8.0m/s. collides with a stationary railroad car of equal mass. after the collision the two cars lock together and slide forward. What is the final velocity of the wrecked cars?
using conservation of energy
M1 = 5.0 x 10^5 kg
M2 = 5.0 x 10^5
Vi1 = 8.0m/s
Vi2 = 0m/s
Vf = ?

Ek = 1/2mv^2

## The Attempt at a Solution

I didn't know where to start, I found the kinetic energy of the railroad car(1.6 x10^7 J) and added it to the stationary one - since it's stationary the railroad car would initially have 0 kinetic energy

mechpeac
My teacher didn't teach us how to solve collision questions using conservation of energy

What type of collision does this scenario represent? What's conserved and what's not conserved in such a collision?

mechpeac
I believe it represents an elastic collision, and conservation of energy/momentenum is conserved. They both lock on together after collision and move as one.

jakeginobi said:
I believe it represents an elastic collision, and conservation of energy/momentenum is conserved. They both lock on together after collision and move as one.
Review the properties of the collision types. You've got things backwards.

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

The principle of collision conservation of energy states that in a closed system, the total amount of energy before a collision is equal to the total amount of energy after the collision. This means that energy cannot be created or destroyed, only transferred or converted from one form to another.

## 2. How is the principle of collision conservation of energy applied in real-world situations?

This principle is applied in various real-world situations, such as car accidents, sports collisions, and billiard games. In these situations, the kinetic energy of the objects involved in the collision is transferred or converted into other forms of energy, such as sound, heat, or potential energy.

## 3. What factors can affect the conservation of energy in a collision?

The conservation of energy in a collision can be affected by factors such as the elasticity of the objects colliding, the mass and velocity of the objects, and external forces such as friction. In an ideal scenario, where there is no loss of energy due to external factors, the principle of conservation of energy holds true.

## 4. How is the principle of collision conservation of energy related to the law of conservation of energy?

The principle of collision conservation of energy is a specific application of the broader law of conservation of energy, which states that energy cannot be created or destroyed, only transformed from one form to another. The principle specifically applies to collisions, where the total energy before and after the collision must remain constant.

## 5. Can the principle of collision conservation of energy be violated?

In an ideal scenario, the principle of collision conservation of energy cannot be violated. However, in real-world situations, there may be external factors that can cause a loss of energy, such as friction or imperfect elasticity. In these cases, the principle may not hold true, but the law of conservation of energy still remains valid.

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