Momentum question -- What quantities are conserved in an elastic collision....

In summary, the conversation is about calculating part d of a problem involving masses and velocities. The equations used include (m2-m1)v0 = m2v2+m1v1 and (m2+m1)v0^2 = m2v2^2 + m1v1^2. The person also knows that v2-v1=2v0 but is unsure how to separate the kinetic energy of mass 2. They also mention getting a strange answer when solving the equations.
  • #1
Clara Chung
304
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Homework Statement


13.png


Homework Equations

The Attempt at a Solution


How do I calculate part d?
I know that (m2-m1)v0 = m2v2+m1v1
where v0 = root (2gh), v1 and v2 are the new velocity of the masses
(m2+m1)v02 = m2v22 + m1v12
I also know that v2-v1=2v0
but how do I separate the KE of mass 2?
 

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  • #2
Clara Chung said:

Homework Statement


View attachment 223719

Homework Equations

The Attempt at a Solution


How do I calculate part d?
I know that (m2-m1)v0 = m2v2+m1v1
where v0 = root (2gh), v1 and v2 are the new velocity of the masses
(m2+m1)v02 = m2v22 + m1v12
I also know that v2-v1=2v0
but how do I separate the KE of mass 2?

It's ##m_1## that is the upper ball. Can you solve the equations to find ##v_1##?
 
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Likes Clara Chung
  • #3
PeroK said:
It's ##m_1## that is the upper ball. Can you solve the equations to find ##v_1##?
I got a very strange answer...
v2-v1=2v0 ...(1)
(m2-m1)v0 = m2v2+m1v1...(2)
After substitution I get -v0=v1...
 

1. What is momentum?

Momentum is a measure of an object's motion, and is calculated by multiplying its mass by its velocity. It is a vector quantity, meaning it has both magnitude and direction.

2. What is an elastic collision?

An elastic collision is a type of collision where both kinetic energy and momentum are conserved. This means that the total momentum and total kinetic energy before and after the collision are equal. In an ideal elastic collision, there is no loss of energy due to friction or heat.

3. What quantities are conserved in an elastic collision?

In an elastic collision, both momentum and kinetic energy are conserved. This means that the total momentum and total kinetic energy of the system before the collision are equal to the total momentum and total kinetic energy after the collision. This conservation is due to the fact that no external forces are acting on the system.

4. How do you calculate the momentum of an object?

The momentum of an object is calculated by multiplying its mass by its velocity. In equation form, it is expressed as p = mv, where p is momentum, m is mass, and v is velocity. The unit for momentum is kg*m/s.

5. Why is momentum conserved in an elastic collision?

In an elastic collision, momentum is conserved due to the law of conservation of momentum. This law states that in a closed system, the total momentum of the system remains constant. In an elastic collision, there are no external forces acting on the system, so the total momentum must remain constant. Additionally, the forces between the colliding objects are equal and opposite, ensuring that the total momentum of the system does not change.

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