#### martillo

**Registered Senior Member**

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 a frame at rest.

One web site:

http://www.braeunig.us/space/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.

Relativity Theory becomes a wrong theory since it is based on a wrong law.

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 a frame at rest.

One web site:

http://www.braeunig.us/space/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.

Relativity Theory becomes a wrong theory since it is based on a wrong law.

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