Conservation of momentum and energy

In summary, when a nucleus at rest splits into two fragments of unequal mass, the fragment with the smaller mass will have a larger speed and kinetic energy, but equal and opposite momentum. This is because the relation between momentum and kinetic energy dictates that they are directly proportional, and since the fragments have equal and opposite momentum, the smaller mass will have a larger kinetic energy. Therefore, the correct answer is D.
  • #1
karis
9
0

Homework Statement



A nucleus originally at rest splits into two fragments of unequal mass. The fragment with smaller mass has a larger
1.momentum
2.speed
3.Kinetic energy

A. 1only
B. 3only
C. 1&2 only
D. 2&3 only
E. 1,2 &3

The Attempt at a Solution


well, i can figure out the speed of the smaller mass will be larger, but how about the momentum and the kinetic energy?
in what way can i determine if they will be larger or not?

The ans is D
Thank You=)
 
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  • #2
Hi karis, wecome to PF.

Since originally the nucleus is at rest, after splitting two fragments must have equal and opposite momentum, irrespective of their unequal masses.
Hence smaller mass must have...speed.
The relation between momentum and kinetic energy can be written as
p = sqrt(2mE) where E is KE.
Since p is the same for both the fragments,
smaller mass will have ...KE.
 
  • #3
Thank you very much:)
 

FAQ: Conservation of momentum and energy

What is the law of conservation of momentum?

The law of conservation of momentum states that the total momentum of a closed system remains constant over time, meaning that the total momentum before an event must be equal to the total momentum after the event.

How does the conservation of momentum affect collisions?

In a closed system, the total momentum must be conserved during a collision. This means that the sum of the momenta of the objects before the collision must be equal to the sum of the momenta after the collision. This is known as the principle of conservation of momentum.

What is the relationship between conservation of energy and conservation of momentum?

The conservation of momentum and conservation of energy are closely related. In a closed system, both the total momentum and the total energy must remain constant. This means that energy cannot be created or destroyed, it can only be transferred from one form to another.

How does the conservation of momentum apply to real-world situations?

The law of conservation of momentum applies to a wide range of real-world situations, such as car crashes, sports, and rocket launches. In all of these situations, the total momentum before and after the event must be conserved.

What are some examples of the conservation of momentum and energy in action?

Some examples of the conservation of momentum and energy include the movement of planets in our solar system, the bouncing of a ball, and the motion of a pendulum. In each of these examples, the total momentum and energy of the system remain constant over time.

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