Real Equation Of Force F = Ma Not Dp/dt

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#1 martillo

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Posted 11 August 2019 - 10:52 AM

This is an extract of "Appendix A" in my manuscript on a new theory which can be accessed through the link in my profile if someone would be interested.

The real Equation of Force is F = ma

Today's Physics is stating that the Equation of Force is F = dp/dt.
We will analyze the equation of motion of rockets to see that the real Equation of Force is:

F = ma

A rocket has variable mass in its trajectory and it's important to see its motion equation.
Let m be its variable mass at any instant in its movement composed by the mass of the rocket plus the mass of its contained fuel.
I have made a search in the internet about rocket motion equations and all the sites agree in the equation:
F = m(dv/dt) = –ve(dm/dt) where ve is the speed of the fuel expelled relative to the rocket.

One web site:
http://www.braeunig....ace/propuls.htm

They all agree that the force acting on the rocket is due to the expelled mass and is F = –ve(dm/dt) and that the equation of motion is F = m(dv/dt) = ma.
I assume the equation have been completely verified experimentally with enough precision from a long time ago.
It is evident that it is used the equation:
F = ma
for the force and not:
F = dp/dt

... ... …

This indicates that today's Physics is wrong stating the Equation of Force as F = dp/dt.

The right equation for force is F = ma even when mass varies.

Note that the natural derivation of the famous equation E = mc2 by Relativity Theory has no sense since it is based in the wrong relation F = dp/dt (http://www.emc2-expl...tm#.XVBNlvZFyM8)
Relativity Theory becomes a wrong theory since it is based on a wrong law.

Edited by martillo, 11 August 2019 - 12:20 PM.

#2 martillo

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Posted 11 August 2019 - 11:14 AM

It must be noted that by definition:

p = mv

Then:

dp/dt = mdv/dt + vdm/dt = ma + vdm/dt

While F = ma (demonstrated by rockets' dynamics)

dp/dt = F + vdm/dt

It follows that F = dp/dt only if dm/dt = 0 meaning constant mass only

#3 Flummoxed

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Posted 17 August 2019 - 12:46 PM

F = ma, hum so what happens when acceleration changes F/a, does your mass suddenly change or perhaps are you accelerating an inertia. Your hypothesis is wrong, very wrong !!.

#4 Dubbelosix

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Posted 26 August 2019 - 03:16 AM

This is an extract of "Appendix A" in my manuscript on a new theory which can be accessed through the link in my profile if someone would be interested.

The real Equation of Force is F = ma

Today's Physics is stating that the Equation of Force is F = dp/dt.
We will analyze the equation of motion of rockets to see that the real Equation of Force is:

F = ma

A rocket has variable mass in its trajectory and it's important to see its motion equation.
Let m be its variable mass at any instant in its movement composed by the mass of the rocket plus the mass of its contained fuel.
I have made a search in the internet about rocket motion equations and all the sites agree in the equation:
F = m(dv/dt) = –ve(dm/dt) where ve is the speed of the fuel expelled relative to the rocket.

One web site:
http://www.braeunig....ace/propuls.htm

They all agree that the force acting on the rocket is due to the expelled mass and is F = –ve(dm/dt) and that the equation of motion is F = m(dv/dt) = ma.
I assume the equation have been completely verified experimentally with enough precision from a long time ago.
It is evident that it is used the equation:
F = ma
for the force and not:
F = dp/dt

... ... …

This indicates that today's Physics is wrong stating the Equation of Force as F = dp/dt.

The right equation for force is F = ma even when mass varies.

Note that the natural derivation of the famous equation E = mc2 by Relativity Theory has no sense since it is based in the wrong relation F = dp/dt (http://www.emc2-expl...tm#.XVBNlvZFyM8)
Relativity Theory becomes a wrong theory since it is based on a wrong law.

Why not use $\frac{dp}{dt}$? I've used the same relativistic description for force a number of times, most widely time I used it was for the new luminosity calculations of moving black holes.