Hi,
I want to determine the Maximum speed of an object, given it’s force, mass and drag. That way I will know how fast the object will go without running my Unity project.
Some sort of calculator were you provide a maximum speed, mass and drag which then outputs the force would be ideal. I’ve been looking around but comming across equations that are complex, using air desnisty and volume.
I’m still looking to calculate the maximum speed (or terminal velocity) though stuggling with these equations. I’ve got a simple calculation of Force / Mass / Drag which so far gets around 8.xxx units above the terminal velocity. Gravity is not being used.
i.e.
where F = 12048, M = 30, D = 1.495, V = 268.63. Terminal velocity in Unity is 260.60. Difference of 8.03.
where F = 20000, M = 50, D = 1.92, V = 208.33. Terminal velocity in Unity is 200.33. Difference of 8.
Any help to get this calculation accurate would be appreciated.
Care to post your equation and code?
The equation is as stated in my second post. Don’t see how writing code would make it any difference?
shrug I generally avoid trying to debug what people are thinking. Good luck with your problem.
I don’t know how to be any clearer, if I knew how to solve the problem I would not be posting on here. If you really need it breaking down then Force divided by Mass divided by Drag is my equation. However, it is not correct, and does not accurately calculate the terminal velocity. All equations I have googled have used surface area of the object, etc, which Unity does not care about. I.e. if I have a cube 1 unit in width, height and length, with 1 unit of mass it will be treated equally as a cube with 100 units in width, height and length with 1 unit of mass. If you do not understand I would rather not have you posting flippant comments, thanks.
I’m a little confused by your post centaurianmudpig. I’m trying to work on something similar where I want the max velocity using the variables of force, mass and drag but when you say that you already posted about your formula it would be nice just to be able to see your code.
For example knowing the method you are using to get your velocity, what your force mode is and so on, might help with figuring out the issue.
Plus I’ve read it a few times to make sure I’m clear but you haven’t really written your formula. At least in a way that makes sense to me.
If you aren’t going to show us the code to help with it at least give us the formula properly like:
F = force applied
D = drag
M = mass
V = max velocity
equation is: V = F/D/M
At least that is the way I read your equation being from your second post, but because you didn’t lay out your equation like above or gave us the code. How can we be absolutely sure.
Hello, i know this post is old but since i fell here, i think it may help a fellow if we had a final answer for this question :
How to compute maximal speed of an object ruled by physic dynamic ?
First, like miroac said, we need to clarify some informations.
From “F = 12048, M = 30, D = 1.495, V = 268.63” i assume D is a drag coefficient you use to simplify the “equations that are complex, using air density and volume” and F is your thrust force.
So i assume you use this kind of formula somewhere in your code to compute your drag force DF (this is where some code would have been nice) :
DF = D * V²
Then you probably compute your acceleration A like so :
A = (F - D * V²) / M
So, now we want the maximum speed.
Maximum speed is reached when there is no more acceleration right ?
At the moment (F - D * V²) / M = 0
So we have :
F - D * V² = 0
V = √(F/D)
This is the formula to get you maximum speed from Mass and Drag coefficient.
PS : Always verify the unit balance of your equation to avoid nonsens.
Considering this, “Speed = Force / Mass / Drag” is obviously wrong,
Speed is m/s
Force is kg.m/s²
Mass is kg
Drag coef (from your simplification) must be kg/m
Thus your are doing m/s = kg.m/s² * 1/kg * m/kg
giving m/s = m²/kg.s²