Reverse engineering potential and kinetic energy

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Discussion Overview

The discussion revolves around the relationships between potential energy (PE), kinetic energy (KE), and momentum, exploring the mathematical derivations and implications of these concepts. Participants examine the nature of energy expressions and the possibility of higher-order derivatives related to mass and velocity.

Discussion Character

  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant proposes that potential energy is represented by the equation PE=M*V and suggests that it is the derivative of kinetic energy, which is defined as KE=(1/2)*(M*V^2).
  • Another participant asserts that momentum is not potential energy and challenges the initial claims, indicating that the reasoning does not hold.
  • A later reply emphasizes that the generalized momentum is related to the derivative of the Lagrangian with respect to generalized velocities, contradicting the initial claim about PE.
  • There is a suggestion that higher-order derivatives could be explored, questioning why the discussion should stop at the second antiderivative (KE) and what physical phenomena might be represented by such expressions.
  • Some participants note that while higher-order differential equations can be constructed, they do not seem to represent natural laws, leading to a lack of interest in pursuing them further.

Areas of Agreement / Disagreement

Participants express disagreement regarding the definitions and relationships between momentum, potential energy, and kinetic energy. There is no consensus on the validity of the initial claims or the implications of higher-order derivatives.

Contextual Notes

Participants highlight that the laws of nature observed thus far are typically described by second-order differential equations, and while higher-order equations can be formulated, they may not correspond to natural laws.

q-ball
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The equation for momentum (potential energy) is PE=M*V.

The equation for kinetic energy is KE=(1/2)*(M*V^2).

You will notice that PE is the derivative of KE. and then you might add that M, simply Mass, is the derivative of PE.

However, because M is simply a scalar quantity, and the other functions are expressions of energy added TO mass, I might suspect the correct approach is to say that you start with mass and take the *antiderivative* with regard to velocity.

and there is more, but first some observations.

PE and KE are two separate expressions of energy. upon inspection we find that they have completely different effects, when an object, let's say a solid ball, encounters a medium:

1A) PE: the solid ball encounters another solid ball. there is an elastic conservation of momentum as the second ball goes off on a particular trajectory, the angle and velocity of which are accounted for by Potential Energy.

1B) PE: the solid ball encounters a wall of oatmeal. exactly how far the ball continues before coming to rest is a function of its momentum (PE), notwithstanding fluid dynamics.

2) KE: the solid ball encounters a thin, hard barrier such as a sheet of glass. if the KE is sufficient, the solid ball will overcome the barrier.

As we can see those are two completely different phenomena. Of course, otherwise they would have the same name, being the same thing. But they don't and they aren't. They are separate phenomena.

Now for the questions.

We can easily deduce a third antiderivative. ??=(1/6)*(M*V^3) so, what sort of energy does that represent? what
physical phenomenon does it describe? as in 1A), 1B), and 2), and ...?

that is what I am most interested in.

but we can also ask, what prevents nature from making use of an infinite array of further antiderivatives in an infinite series of discrete expressions of energy? who says we must stop at the second antiderivative (KE)? Shouldn't there be a name for this set of equations, this class of expression, which goes from the 0th to the nth antiderivative of Mass with regard to Velocity?
 
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q-ball said:
The equation for momentum (potential energy) is PE=M*V.
Momentum is not potential energy. Momentum is not energy. So the rest of your post doesn't really make sense.

I've downgraded the thread level from A to I.
 
q-ball said:
The equation for momentum (potential energy) is PE=M*V.
No, momentum is not PE.

q-ball said:
notice that PE is the derivative of KE
No, the closest that you could come to this is that the generalized momentum is the derivative of the Lagrangian with respect to the generalized velocities.

q-ball said:
who says we must stop at the second antiderivative (KE)?
The laws of nature that we have observed thus far are second order differential equations with respect to the coordinates. There is nothing mathematically preventing you from constructing higher order differential equations, but they don't seem to represent natural laws so most people don't bother.
 
Dale said:
The laws of nature that we have observed thus far are second order differential equations with respect to the coordinates. There is nothing mathematically preventing you from constructing higher order differential equations, but they don't seem to represent natural laws so most people don't bother.
I suppose that answers the question then.
 

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