Can the kinetic energy of a system be negative?

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SUMMARY

The kinetic energy (KE) of a system cannot be negative due to its dependence on mass and the square of velocity, as outlined in the kinetic energy formula KE = 0.5 * m * v². While mass is always a positive value, even if velocity is negative, the squaring of velocity ensures that KE remains non-negative. In contrast, gravitational potential energy can be negative based on the chosen reference point for zero potential energy, but only changes in potential energy affect kinetic energy and force exertion.

PREREQUISITES
  • Understanding of kinetic energy formula (KE = 0.5 * m * v²)
  • Basic concepts of gravitational potential energy
  • Familiarity with reference points in physics
  • Knowledge of energy conservation principles
NEXT STEPS
  • Study the implications of reference points on gravitational potential energy
  • Explore the relationship between kinetic energy and work-energy theorem
  • Investigate scenarios where potential energy changes affect kinetic energy
  • Learn about energy conservation in closed systems
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Students of physics, educators teaching energy concepts, and anyone interested in understanding the principles of kinetic and potential energy in mechanical systems.

meredith
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what about the gravitational potential energy of a system?

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2. Homework Equations
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Nope. Think of the formula for KE. Mass is never negative, and even if the velocity is negative, its squared so the negative sign goes away.

Gravitational Potential can be negative depending on where you define your potential to be zero. But really, only changes in potential energy are relevant. Its only when the gravitational potential energy changes that the KE changes, a force is exerted, etc.
 

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