Understanding the Relationship Between Force, Momentum, and Impulse

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Discussion Overview

The discussion explores the relationship between force, momentum, and impulse, focusing on their definitions and interconnections in physics. Participants examine how these concepts relate to changes in motion and the effects of time on force and momentum, with examples illustrating the practical implications of these relationships.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions whether force is related to momentum or vice versa, referencing the equations F=ma and P=mv.
  • Another participant suggests that the link between force and momentum is time, proposing that force applied over time changes an object's momentum, leading to the formulation F = P/t.
  • A further contribution introduces calculus, stating that force can be expressed as F=dp/dt under certain conditions, indicating a more instantaneous relationship between force and momentum.
  • Impulse is introduced as a concept with the same dimensions as momentum, defined as force acting over time, with an example involving the dropping of an egg on different surfaces to illustrate the effects of impulse on force and momentum.

Areas of Agreement / Disagreement

Participants present multiple viewpoints on the relationship between force, momentum, and impulse, with no consensus reached on a singular interpretation or model. The discussion remains open to various interpretations and examples.

Contextual Notes

Some assumptions about the conditions under which the equations apply are not fully explored, such as the implications of mass change in different scenarios (e.g., rockets). The discussion also does not resolve the nuances of how time affects force and momentum in various contexts.

zeshkani
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Is force related to Momentum or momentum to force in anyway
F=ma and P=mv
 
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Yes, the link between the two is time. Essentially, force is applied over time to change an objects momentum.

Because F = m a, and a =[tex]\Delta[/tex]v / t
then F = m v/t
As you said P = mv so we get
F = P/t or P = Ft
 
With calculus, the equations become more instantaneous and exact:

F=ma=m(dv/dt)=dp/dt-v(dm/dt).

If dm=0 (for instance, not a rocket) then:

F=dp/dt
 
thx a lot :)
 
Also, do you know the concept of Impulse? It has the same dimensions of momentum, but is more precisely defined as a Force acting over a certain amount of time. That's why when you drop an egg on a pillow, it will not break, but when you drop an egg on concrete, it will. Because the egg has some mass m and velocity v, and therefore some momentum p = mv, this momentum is numerically equal to the reactive force of the ground(or pillow) multiplied by the time interval it spends on that respective surface.

The pillow cushions the fall and therefore increases the time interval, in effect decreasing the force and keeping the egg from breaking. When you drop it on the concrete, the time interval is very short, and so the force on the egg is large (which is why it breaks).
 

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