Conservation of momentum in an inelastic collision with friction

In summary, the conversation discusses the momentum of a ball falling into a truck loaded with sand and the effects of a collision. In the vertical direction, the momentum before the collision is mcosv and after the collision, the ball sinks into the sand. In the horizontal direction, the momentum before the collision is msinv and after the collision, it should be (m+M)v' depending on whether friction is present. The conversation also briefly touches on the relationship between temperature and the speed of particles in a substance, but this is not necessary for solving the problem.
  • #1
DanicaK
32
0

Homework Statement


a ball falls in a truck loaded with sand with velocity v having horizontal and vertical component. The angle under which it enters the truck is α, the mass of the ball is m of the track loaded with sand is M. What happens with the momentum after the collision?


The Attempt at a Solution


This should be considered as completely inelastic collision.
In vertical direction the momentum before the collision is the momentum of the ball mcosv.
After the collision the track is not moving in horizontal direction, but the momentum should be conserved. The ball sinks in the sand, so is this the explanation?
In horizontal direction the momentum before the collision is msinv. What is the momentum after? There is friction during the collision. It should be (m+M)v', but what about the friction?
 
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  • #2
What happens to the temperature of the sand once the ball makes contact?
 
  • #3
It does not effect the momentum.
 
  • #4
really? what does temperature tell you about the speed of particles in a substance?
 
  • #5
DanicaK said:
In horizontal direction the momentum before the collision is msinv. What is the momentum after?
If there is no external horizontal force on the system (the truck, sand, and the ball), then momentum is conserved in the horizontal direction. So it really depends on whether you are allowed to neglect friction, which would be a horizontal force if it is present.

In introductory physics, if there is no mention of friction then it is usually neglected. So it looks like conservation of momentum (in the horizontal direction) applies here. And you know that momentum before the collision is m·sinα·v

p.s. Don't worry about the temperature, that is unnecessary for solving this problem.
 
  • #6
Actually I am university student.
 

1. What is conservation of momentum in an inelastic collision with friction?

Conservation of momentum in an inelastic collision with friction is a fundamental principle in physics that states that the total momentum of a system remains constant before and after the collision, even if there is friction present. This means that the total momentum of the objects involved in the collision does not change, but rather is transferred between the objects.

2. How does friction affect the conservation of momentum in an inelastic collision?

Friction plays a crucial role in an inelastic collision as it causes a decrease in the overall kinetic energy of the system. This decrease in energy is balanced by an increase in the internal energy of the objects, such as heat. However, despite this decrease in energy, the total momentum of the system remains constant.

3. What is an example of an inelastic collision with friction?

An example of an inelastic collision with friction is two cars colliding on a road. As the cars collide, there is friction between their surfaces, causing a decrease in their kinetic energy. However, the total momentum of the system remains constant, and the cars will continue to move together after the collision.

4. How is the conservation of momentum in an inelastic collision with friction calculated?

The conservation of momentum in an inelastic collision with friction can be calculated using the equation: m1v1 + m2v2 = (m1 + m2)vf. In this equation, m1 and m2 are the masses of the two objects, v1 and v2 are their initial velocities, and vf is their final velocity after the collision.

5. What are the real-life applications of conservation of momentum in an inelastic collision with friction?

The conservation of momentum in an inelastic collision with friction has various real-life applications, including car crashes, sports, and ballistics. Understanding this principle is crucial in designing safety features in vehicles and predicting the outcome of collisions in sports, such as billiards or bowling. It is also essential in understanding the trajectory and impact of projectiles, such as bullets or rockets.

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