Projectile motion air resistance calculator - tutorial?

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Discussion Overview

The discussion revolves around calculating air resistance in projectile motion, specifically using a Texas Instruments TI-84 Plus calculator. Participants explore the necessary formulas and methods for incorporating air resistance into projectile motion calculations, addressing both theoretical and practical aspects.

Discussion Character

  • Technical explanation
  • Homework-related
  • Debate/contested

Main Points Raised

  • One participant requests a tutorial for calculating air resistance in projectile motion and provides specific values for the calculation.
  • Another participant presents a set of differential equations that describe the motion of a projectile under the influence of air resistance, assuming a constant drag coefficient.
  • A later reply indicates progress in using the calculator but seeks clarification on how to incorporate air resistance into the existing calculations.
  • There is a question about whether the drag coefficient remains constant or changes over time due to factors like the projectile's shape.

Areas of Agreement / Disagreement

Participants do not reach a consensus on how to incorporate air resistance into the calculations, and there are differing levels of understanding regarding the implications of a constant versus variable drag coefficient.

Contextual Notes

The discussion includes assumptions about the drag coefficient and the need for integration of differential equations, which may not be fully understood by all participants. There are also unresolved steps in the calculation process as participants seek further guidance.

Pega
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Projectile motion air resistance calculator - tutorial??

I am not familiar with the terms/words of physics in English, but I hope you can excuse me.

I need a tutorial for how to calculate the air resistance in a projectile motion. I want to do it with my calculator and that's why I came here. I wonder if any of you might know about such a tutorial, or if you want to guide me right here.

I use a Texas Instruments TI-84 Plus.

If you want to guide me right here it would be for my advantage to use these values:

Formula --> F = (1/2)CρAv2

C = 0.45
Air density ρ = 1.22 kg/m3
Mass m = 2.58 g
A = π*r2, r = 1.91 cm
V0 = 25 m/s
anlge = 40°

Please try to be clear when explain.
 
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*bump*
 


I see you assume a constant drag coefficient; a nice fact because it simplifies the analysis.
I also assume you know how to integrate a system of differential equations.
Mr Newton says:

dVx/dt=(-1/2 C rho A V^2 cos(theta))/m
dVy/dt=(-g-1/2 C rho A V^2 sin(theta))/m
dx/dt=Vx
dy/dt=Vy

This is the set of four differential equations I mentioned above.

And the additional relationships:

V^2=Vx^2+Vy^2
cos(theta)=Vx/V
sin(theta)=Vy/V
 


I read the manual for my calculator and now I have gotten further.
Down below I show you print screens of how far I've gotten. Then hopefully you understand what I've done and will help me the last bit.
Skärm1.jpg
Skärm2.jpg
Skärm3.jpg


As you see I've managed to put in the projectile motion without air resistance. So how do I put in the air resistance in this?
I'm not sure if I have understood all of what you wrote, but I think that if you/someone show me what to do here, I will get it.
I see you assume a constant drag coefficient; a nice fact because it simplifies the analysis.
So if I were to use this practically, you mean that the drag coefficient would differ over time?? (I'm not that well-grounded in this subject) Because of the projectile changing shape? Or of some other more advanced physical explenation?

Thanks for your time.
 


*bump*
 


*bump*
 

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