Why is linear momentum not conserved or realistic here?

In summary, the conversation revolves around demonstrating that linear momentum is not conserved or unrealistic in a given situation. The assumptions include no friction, velocity being constant, and an elastic collision. The problem is figuring out how to calculate the force required for Godzilla to push both Megalon and Jet Jaguar. The conversation also discusses the violation of conservation of momentum in science fiction and suggests making an estimate of total momentum before and after the collision. It is clarified that this is a homework question and the person should post it in the appropriate forum with a properly filled out template.
  • #1
Gusta257
- This is the situation provided where it has to be demonstrated that linear momentum is not conserved or unrealistic. My assumptions are: there's no friction due to how Godzilla is moving, the sand is acting as a lubricant. Velocity is constant. This is an elastic collision. I also guess that we have to calculate the force that Godzilla applies on the two masses combined (Megalon and Jet Jaguar) in order to prove that the force required for Godzilla to push both Megalon and Jet Jaguar is unrealistic.

My problem is, I don't really know how to calculate the force that Godzilla applies on both masses. And if that's not what's need to calculate, then I really don't have an idea of what to calculate to prove linear momentum is not conserved/unrealistic.
 
Physics news on Phys.org
  • #2
If I understand properly, you want to demonstrate that what happens in the video clip is impossible because it implies a violation of conservation of momentum? Is this a homework/ coursework question?

You should be able to make a reasonable estimate of the total momentum before and after the collision from reasonable estimates of the mass of the participants and their before and after speeds.
 
  • #3
Science fiction like this rarely cares about conservation of momentum. The authors simply ignore it. In this particular case I don't see an obvious violation of it. The sliding approach looks really unrealistic, however.
 
  • #4
Nugatory said:
If I understand properly, you want to demonstrate that what happens in the video clip is impossible because it implies a violation of conservation of momentum? Is this a homework/ coursework question?

You should be able to make a reasonable estimate of the total momentum before and after the collision from reasonable estimates of the mass of the participants and their before and after speeds.
Yes to both questions, this is a homework question. So I only need to calculated momentum before and after?
 
  • #5
Gusta257 said:
Yes to both questions, this is a homework question. So I only need to calculated momentum before and after?
Because it is a homework question, you'll want to post it in the homework forum: https://www.physicsforums.com/forums/introductory-physics-homework.153/
Start a new thread there... and fill out the template properly when you do.

This thread is closed.
 

1. Why is linear momentum not conserved in collisions?

Linear momentum is not always conserved in collisions because external forces, such as friction or air resistance, can act on the objects involved. These external forces can change the total momentum of the system, making it different before and after the collision.

2. What factors can affect the conservation of linear momentum?

The conservation of linear momentum can be affected by factors such as external forces, the elasticity of the objects involved, and the type of collision (elastic or inelastic). In elastic collisions, momentum is conserved, while in inelastic collisions, some of the kinetic energy is converted into other forms of energy and momentum may not be conserved.

3. Is linear momentum realistic in all situations?

No, linear momentum is not always realistic in all situations. In classical mechanics, linear momentum is conserved in idealized situations where there are no external forces acting on the objects involved. In reality, external forces are always present and can change the total momentum of a system.

4. How does the conservation of linear momentum relate to Newton's Third Law of Motion?

The conservation of linear momentum is related to Newton's Third Law of Motion, which states that for every action, there is an equal and opposite reaction. In collisions, the objects involved exert equal and opposite forces on each other, resulting in a conservation of momentum.

5. Can linear momentum be regained after it is lost?

In a closed system where external forces are not present, the total momentum of the system cannot be regained once it is lost. However, in open systems where external forces are present, the total momentum can be regained through the application of external forces.

Similar threads

Conservation of linear and angular momentum
    • Mechanics
Replies
9
Views
1K
I Conservation of angular momentum during collisions
    • Mechanics
Replies
3
Views
1K
B Why is KE not conserved when momentum is?
    • Mechanics
2
Replies
53
Views
2K
B Conservation of momentum and conservation of energy details
    • Mechanics
Replies
30
Views
2K
B Conservation of momentum in a closed system
    • Mechanics
Replies
3
Views
980
Conservation of Angular Momentum is Dumbfounding
    • Mechanics
2
Replies
36
Views
14K
Conservation of linear momentum in this system
    • Mechanics
Replies
4
Views
2K
B Understanding Physics for Coding Collision of 2 Balls
    • Mechanics
Replies
14
Views
1K
Linear momentum in oblique collisions and generally
    • Mechanics
Replies
8
Views
3K
Conservation of linear momentum when wheels are included
    • Mechanics
Replies
11
Views
2K

Hot Threads

Recent Insights

Back
Top