Why does an object have kinetic energy even when it's not moving?

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Homework Help Overview

The discussion revolves around the concept of kinetic energy, particularly questioning how an object can possess kinetic energy when it is stationary. The original poster is exploring the relationship between motion, reference frames, and kinetic energy.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are examining the dependency of kinetic energy on the observer's reference frame. One participant provides an example involving a moving car and a stationary ball to illustrate this point.

Discussion Status

The discussion is active, with participants engaging in the exploration of how kinetic energy is perceived differently based on the observer's motion. There is an acknowledgment of the concept that kinetic energy may not be absolute, but no consensus has been reached.

Contextual Notes

Participants are questioning the definitions and assumptions surrounding kinetic energy, particularly in relation to stationary objects and the influence of different reference frames. There is also a mention of a mathematical expression, though its relevance to the kinetic energy discussion is unclear.

courtrigrad
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Hello all

I was just wondering if an object is stationary, how can it still possesses kinetic energy? Is it due to the reference frame? Does everything possesses kinetic energy?

Thanks
 
Last edited:
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any ideas?
 
you are right, kinetic energy depends on the reference frame, how? let me show you an example.
lets say you are in a car which traveling 60mile/hr, and holding a metal ball STATIONARY on your hand, for you, the ball has no kinetics energy, but for me (who standing on the ground), the ball carries a huge kinetics energy, how to prove it? easy, when your car passes by me, throw the ball out and see how much demage the ball will do...
conclution: the kinetic energy is depended on the motion of the observer, there are no such thing call absulote kinetic energy,
 
thanks a lot

just a test:

[tex]a^{2}+\frac{1}{a^{2}}+2(a+\frac{1}{a})=7[/tex]
 
Last edited:

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