Problem with perfectly inelastic collisions.

In summary, the conversation discusses an inelastic collision between two trucks. It is mentioned that the collision is perfectly inelastic and there is a question about how momentum is conserved when there is no kinetic energy left. The response clarifies that inelastic collisions are determined by conservation of momentum and not necessarily by the loss of all kinetic energy. In the example provided, the resulting velocity would be one third of the initial velocity if both trucks are moving at the same speed.
  • #1
Cherryboba
2
0
Two trucks, one twice as heavy as the other, collide head on (assume it's one dimensional and easy ;) ) and the collission is perfectly inelastic. If it was perfectly inelastic there would be no kinetic energy left, and therefore no velocity. How do the trucks manage to conserve momentum by moving in the direction of the smaller truck if they have no energy?

Please help out, I've been searching for days.
 
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  • #2
An inelastic collision isn't necessarily one in which all of the kinetic energy is lost. Its simply one in which the kinetic energy isn't necessarily conserved.

Inelastic collisions are determined by conservation of momentum alone. In your example, if both trucks are going at the same speed, they would have a resulting velocity (one third of the initial).
 

1. What is a perfectly inelastic collision?

A perfectly inelastic collision is a type of collision where two objects collide and stick together, resulting in a loss of kinetic energy. This means that the objects move together as one mass after the collision.

2. What causes a perfectly inelastic collision?

A perfectly inelastic collision occurs when there is a transfer of kinetic energy into other forms of energy, such as heat or sound. This can be caused by the objects deforming upon impact or by objects with adhesive properties.

3. How is the momentum conserved in a perfectly inelastic collision?

In a perfectly inelastic collision, the total momentum of the objects before and after the collision remains constant. This is because the objects stick together and move as one mass, so the total momentum is the same before and after the collision.

4. What is the difference between a perfectly inelastic collision and an elastic collision?

In an elastic collision, the objects bounce off each other after impact and the kinetic energy is conserved. In a perfectly inelastic collision, the objects stick together and there is a loss of kinetic energy as it is converted into other forms of energy.

5. How do you calculate the final velocity in a perfectly inelastic collision?

To calculate the final velocity in a perfectly inelastic collision, you can use the law of conservation of momentum. This states that the total momentum before the collision is equal to the total momentum after the collision. You can set up an equation using the masses and velocities of the objects to solve for the final velocity.

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