Basic question about kinetic energy and momentum

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SUMMARY

The discussion confirms the relationships between kinetic energy (KE) and momentum (p) as true based on the mathematical equations provided. Specifically, it states that if kinetic energy decreases while mass remains constant, momentum decreases. Conversely, if kinetic energy remains constant and mass decreases, momentum also decreases. Additionally, an increase in kinetic energy with constant mass results in increased momentum, and an increase in mass with constant kinetic energy leads to increased momentum. The key equation referenced is KE = p²/(2m).

PREREQUISITES
  • Understanding of basic physics concepts such as kinetic energy and momentum.
  • Familiarity with algebraic manipulation of equations.
  • Knowledge of the relationship between mass, velocity, and energy.
  • Basic grasp of proportional relationships in physics.
NEXT STEPS
  • Study the derivation of the equation KE = p²/(2m).
  • Explore the implications of mass and velocity changes on momentum and kinetic energy.
  • Learn about conservation laws in physics, particularly in elastic and inelastic collisions.
  • Investigate real-world applications of kinetic energy and momentum in sports and vehicle dynamics.
USEFUL FOR

Students of physics, educators teaching mechanics, and anyone interested in understanding the fundamental principles of motion and energy relationships.

grayb
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Hi, I'm learning about momentum and kinetic energy and I wanted to know if the following relationships are true. I think they are true, but I am not sure:

  1. If kinetic energy goes down and mass stays constant, momentum goes down
  2. If kinetic energy stays constant and mass goes down, momentum goes down
  3. If kinetic energy goes up and mass stays constant, then momentum goes up
  4. If kinetic energy is constant and mass goes up, momentum goes up

Are they true? Thank you.
 
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Have you done the math? If so, what does the math say? Remember, the math won't lie.
 
All true.

KE = p^{2}/(2m)

Now, for constant mass:
KE \propto p^{2}

For constant kinetic energy:
m \propto p^{2}
 

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