How Do You Calculate Position, Velocity, and Acceleration from d(x)/d(t) = c/x?

  • Context: Graduate 
  • Thread starter Thread starter 69911e
  • Start date Start date
Click For Summary

Discussion Overview

The discussion revolves around the calculation of position, velocity, and acceleration from the equation d(x)/d(t) = c/x, where c is a constant. Participants are exploring the integration of this equation and the subsequent derivation of related equations for motion over time.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Homework-related

Main Points Raised

  • One participant presents the equation v = c/x and attempts to derive equations for position, velocity, and acceleration but expresses uncertainty in their integration steps.
  • Another participant questions the justification for a specific integration step involving ln(x), indicating a potential error in the derivation.
  • There is a repeated inquiry about the origin of ln(x) in the integration process, suggesting confusion over the mathematical steps taken.
  • A participant points out that the original equation can be rewritten in a clearer form, leading to the separation of variables and integration, but acknowledges that the integration results may not have been correctly applied.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the correct integration steps or the derivation of the equations for position, velocity, and acceleration. Multiple competing views on the integration process and its implications remain unresolved.

Contextual Notes

Limitations include unclear assumptions regarding the integration steps and the dependence on the correct interpretation of the equation. The discussion highlights unresolved mathematical steps and potential misinterpretations of integration results.

69911e
Messages
30
Reaction score
1
I have the equation v=c/x
d(x)/d(t)=c/x
velocity= c(constant)/x (distance)

I need equations to calculate position, velocity and acceleration for a given time,
My attempt was:
xdx=cdt
x2ln(x)=ct
elnxx2=ekt
xx2=ekt
but I need x(t)v(t),a(t)

Any suggestions on how to calculate?
 
Physics news on Phys.org
You start of well with ##xdx = cdt##
The next step is wrong. How do you justify ##\int xdx = x^2 \text{ln}(x)##?
Because that's what happens there.

If you know ##x(t)## how can you find ##v(t)## and ##a(t)##?

You've already used how you get ##v(t)##
 
Where did the ln(x) come from??
 
HomogenousCow said:
Where did the ln(x) come from??
I did int of XDx= x2*(Dx/x)=
x2LN(x)

That was the wrong move...

Thanks
 
69911e said:
I have the equation v=c/x
d(x)/d(t)=c/x
Usually, posters don't include enough parentheses, but here you have more than you need, which might have led to some confusion.

The above can be written as ##\frac{dx}{dt} = \frac c x##. Separating, we get x dx = c dt. Integrating, we get ##\frac 1 2 x^2 = ct + K##.
69911e said:
velocity= c(constant)/x (distance)

I need equations to calculate position, velocity and acceleration for a given time,
My attempt was:
xdx=cdt
x2ln(x)=ct
elnxx2=ekt
xx2=ekt
but I need x(t)v(t),a(t)

Any suggestions on how to calculate?
 

Similar threads

  • · Replies 0 ·
Replies
0
Views
4K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 2 ·
Replies
2
Views
3K
Replies
7
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 0 ·
Replies
0
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 12 ·
Replies
12
Views
3K