Elastic Collisions between two objects

In summary: The equation provided is the conservation of momentum equation. In summary, the question is asking for the relative speed of two siblings after an elastic collision on an iced-over pond. The equation provided is the conservation of momentum equation, which is used to solve for the relative speed.
  • #1
Flinze
23
1

Homework Statement


You have an inertia of 52 kg and are standing at rest on an iced-over pond in your skates. Suddenly, your 60-kg brother skates in from the right with x component of velocity -4.9 m/s and collides elastically with you.

1. What is the siblings' relative speed after the collision?

Homework Equations


m1v1+m2v2=m1v1+m2v2

The Attempt at a Solution


WvlUmrX.png

This is part of my assignment online, and it when I plug in 4.55 m/s it says my answer is incorrect. I'm lost at this point.
Thanks in advance!
 
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  • #2
Flinze said:

Homework Statement


You have an inertia of 52 kg and are standing at rest on an iced-over pond in your skates. Suddenly, your 60-kg brother skates in from the right with x component of velocity -4.9 m/s and collides elastically with you.

1. What is the siblings' relative speed after the collision?

Homework Equations


m1v1+m2v2=m1v1+m2v2
Has the above equation any information? It is a trivial identity.

Flinze said:

The Attempt at a Solution


WvlUmrX.png

This is part of my assignment online, and it when I plug in 4.55 m/s it says my answer is incorrect. I'm lost at this point.
Thanks in advance!
Relative with respect what?
The question is the relative speed of you and your brother after the collision.
 

1. What is an elastic collision?

An elastic collision is a type of collision between two objects where there is no loss of kinetic energy. This means that the total kinetic energy before the collision is equal to the total kinetic energy after the collision.

2. How is momentum conserved in an elastic collision?

According to the law of conservation of momentum, the total momentum of a closed system remains constant. In an elastic collision, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision. This ensures that momentum is conserved.

3. What is the difference between an elastic collision and an inelastic collision?

In an inelastic collision, there is a loss of kinetic energy due to the objects sticking together or being permanently deformed. In contrast, an elastic collision involves no loss of kinetic energy and the objects bounce off each other without any change in shape or size.

4. How can the coefficient of restitution be used to determine if a collision is elastic?

The coefficient of restitution (e) is a measure of the elasticity of a collision. It is equal to the ratio of the relative velocities of the two objects before and after the collision. In an elastic collision, the coefficient of restitution will be equal to 1, while in an inelastic collision, it will be less than 1.

5. What factors can affect the elasticity of a collision?

The elasticity of a collision can be affected by factors such as the nature of the materials involved, the angle of collision, and the presence of external forces. In general, collisions between objects with higher elastic properties and smaller angles of collision tend to be more elastic. External forces, such as friction, can also decrease the elasticity of a collision.

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