Newton's second law integration

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The discussion revolves around integrating Newton's second law, specifically the equation mdv/F(v) = dt, to derive the relationship t = m ∫(dv/F(v)). Participants clarify how to handle the integration, emphasizing that the variable inside the integral can differ from the limits of integration. They discuss the implications of using a constant force F(v) = Fo, leading to the conclusion that the resulting motion is linear with constant acceleration. The conversation highlights the importance of correctly interpreting variables and their roles in integration, ultimately reinforcing the linear nature of the motion described.
  • #31
Oblio said:
I thought we subbed F(v) out of the integral?

Yes. what do you get when you do that?
 
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  • #32
t =mF(v) \int^{v}_{vo} dv
 
  • #33
Oblio said:
t =mF(v) \int^{v}_{vo} dv

before you take out F(v), you should replace it with Fo... so what do you get when you solve for v?
 
  • #34
t= mF(o) \int^{v}_{vo} dv

t= mF(o) (v-vo)

solve for v from here?
 
  • #35
Oblio said:
t= mF(o) \int^{v}_{vo} dv

t= mF(o) (v-vo)

solve for v from here?

Yes, one thing though, it should be m/Fo because the F(v) was in the denominator not the numerator.
 
  • #36
Typo. my bad

v = F(o)t / m + V(o) ?
 
  • #37
Oblio said:
Typo. my bad

v = F(o)t / m + V(o) ?

yup.
 
  • #38
So... why is this especially significant? They want to see some kind of comment.
Something to do with velocity dependence?
 
  • #39
Oblio said:
So... why is this especially significant? They want to see some kind of comment.
Something to do with velocity dependence?

What kind of motion is it?

v = F(o)t / m + V(o)

describe the kind of motion the object is undergoing.
 
  • #40
the motion would be linear i believe
 
  • #41
Oblio said:
the motion would be linear i believe

Yes, velocity is changing linearly. What about the acceleration?
 
  • #42
YES! your back :)
um...

increasing with time?
 
  • #43
Oblio said:
YES! your back :)
um...

:)

increasing with time?

nope.
 
  • #44
also constant?
 
  • #45
Oblio said:
also constant?

yes. compare:

v = v0 + at

with

v = v0 + (Fo/m)t

the equations have the same form.
 
  • #46
O ya!
I can say both are linear then?
 
  • #47
Oblio said:
O ya!
I can say both are linear then?

Well, linear with constant acceleration. Linear just means the object moves along a straight line.
 
  • #48
Yeah, understood.
 

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