Momentum vs inertia

[Galaxion]

TL;DR

Momentum physical meaning

Can momentum considered as the resistance of a force? Why?I noticed that the physical meaning of momentum and inertia are similar

 

[russ_watters]

No, I don't think so. Inertia (mass) could be considered resistance to acceleration due to applied force via a=f/m. I'm not even sure what "resistance of a force" would mean physically/mathematically.

 

[Ibix]

Inertia is how hard it is to make something change its state of motion, which is essentially mass.

 

[Matterwave]

A body at rest still has inertia even though it has no momentum.

 

[sophiecentaur]

A body at rest still has inertia even though it has no momentum.

Momentum is frame dependent; the velocity is relative to a reference velocity. Your "rest" is not a particularly special situation (to a Physicist).

Mass is not frame dependent. Mass and Inertia are pretty much in the same neck of the woods and the use of the words depends on the context and the audience when 'explaining' the same phenomenon.

 

[wrobel]

TL;DR: Momentum physical meaning

Can momentum considered as the resistance of a force? Why?I

I doubt that the answer to your question, whatever it may be, will help you in any way when setting up the system's equations of motion.

 

[Herman Trivilino]

the resistance of a force?

There's no such thing as resistance of a force.

 

[Dale]

TL;DR: Momentum physical meaning

Can momentum considered as the resistance of a force?

I think that would be mass. Resistance comes from Ohm’s law: $V=RI$. If you analogize a force in Ohms law you would probably say a force is analogous to the voltage.

In Newton’s 2nd law you can write it in terms of momentum $F=dp/dt$, but that doesn’t clearly map to Ohm’s law. But if you write it in terms of mass then $F=ma$. This more clearly maps to Ohm’s law with force mapping to voltage, acceleration mapping to current, and mass mapping to resistance.

 

[Paul Colby]

Also, for Ohms law, current flowing through a resistor dissipates energy in the form of heat. For Newton, force goes into kinetic energy. This process is reversible. A closer mechanical analogy would be a loss term $F=-\alpha \frac{dx}{dt}$.

 

[Herman Trivilino]

I noticed that the physical meaning of momentum and inertia are similar

Can you expand on this a bit? In what way are they similar?

To most people inertia is synonymous with mass $m$.

Momentum is $m \vec{v}$, where $\vec{v}$ is the velocity.

Note that mass is a scalar quantity whereas momentum is a vector quantity.

 

[sophiecentaur]

Resistance comes from Ohm’s law: V=RI.

When trying to use an analogy to explain something then it is important that the analogy is valid. Ohm's Law states that the ratio of V/I is constant for a metal at constant temperature. That ratio is referred to as the Resistance. Merely quoting the ratio of volts to current in any old conductor is not "Ohm's Law" because V is not always proportional to I. I have come to terms with this sloppiness being common on PF but, in this context you really have to question the validity of quoting Ohm's law. It's rather the reverse actually: Newton's second law is a law because mass doesn't change but an invariant Resistance is a very rare occurrence.

This is really not just being picky.