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CurrentOverflow
Mad Scientist
Canada
311 Posts |
 Posted - Jan 31 2007 : 9:39:44 PM
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| Does any one know the equation that find acceleration of an object on an inclined plane WITH friction, thank you :) |
~Mike~
Theres 10 kinds of people, those who understand binary and those who don't |
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cyclopsitis
Nobel Prize Winner
Canada
732 Posts |
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CurrentOverflow
Mad Scientist
Canada
311 Posts |
Posted - Feb 03 2007 : 9:53:01 PM
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Thanks for your help.
Velocity
v = c tanh(aT/c)
c is what? T= time right? ooohhh you mean mu right? (micro symbol) and ok thanks i think i get it now
However the formula I was looking for involved sin and cos.
Thanks once again |
~Mike~
Theres 10 kinds of people, those who understand binary and those who don't |
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cyclopsitis
Nobel Prize Winner
Canada
732 Posts |
Posted - Feb 03 2007 : 9:56:24 PM
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Glad it could help. I don't have books on velocity stuff but I have lots of formulas using sin, cos, and tan for electrical stuff :D haha but that dosn’t help here!
glad it helped!
Ken |
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CurrentOverflow
Mad Scientist
Canada
311 Posts |
Posted - Feb 03 2007 : 10:10:24 PM
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I found the formula after 5 pages of google!!!!
a= g(sin(theta)-c(cos(theta)))
Yay no more finding Fnet :):):) |
~Mike~
Theres 10 kinds of people, those who understand binary and those who don't |
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cyclopsitis
Nobel Prize Winner
Canada
732 Posts |
Posted - Feb 05 2007 : 6:16:30 PM
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Good! I rarely put things into Google because it takes forever to find what you want and when you do find it, it turns out to be a blog and of no help at all! lol. So it can be frustrating!! haha. Glad you found what you needed though! I hope you have a decent scientific calculator for all that lol. I have the tables for sin, theta, and cos if you want them. I have used them when I dont have a calculator handy!
Ken |
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Binary 1011001101
Nobel Prize Winner
United Kingdom
569 Posts |
Posted - Feb 06 2007 : 02:24:50 AM
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| On the topic of maths and equations, I need to find out the peak discharge current of a 3500uF capacitor at 107V through 1.7ohms. I have looked on google and found complicated maths stuff that I dont understand, and no nice calculators where I type the number in and it kicks out the answer, thanks. |
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pebe
Nobel Prize Winner
United Kingdom
1078 Posts |
Posted - Feb 06 2007 : 04:19:11 AM
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If the capacitor is a 'perfect' one, ie. it has no series resistance, then the peak discharge current will flow when the capacitor is first connected to the resistor. It will start at 62.94A (107v/1.7ohms) and reduce exponentially. The size of capacitor will only alter the rate at which the current reduces - not the peak value of the current.
If the capacitor has series resistance (and a 3500uF would probably be an electrolytic - which certainly has) then add the series resistance to the 1.7ohms for the calculation. |
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Binary 1011001101
Nobel Prize Winner
United Kingdom
569 Posts |
Posted - Feb 06 2007 : 12:26:56 PM
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If the size of the capacitor affects the time it is "on" for I would want a small capacitor if I want to acheve a short high current pulse, right?
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pebe
Nobel Prize Winner
United Kingdom
1078 Posts |
Posted - Feb 06 2007 : 3:04:33 PM
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Yes, the time is proportional to C*R.
I thought your first question with the C and R quoted was academic to establish the principle involved. But have you a specific application in mind? |
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Binary 1011001101
Nobel Prize Winner
United Kingdom
569 Posts |
Posted - Feb 06 2007 : 3:29:28 PM
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Sorry that I am so stupid, I don't understand what you mean by
"academic to establish the principle involved"
I am crap at maths and english!
The application is a coilgun, see www.munkey.co.nr to see what ive done. |
Edited by - Binary 1011001101 on Feb 06 2007 3:35:11 PM |
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cyclopsitis
Nobel Prize Winner
Canada
732 Posts |
Posted - Feb 06 2007 : 3:32:59 PM
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The formula you can use is t=R X C
example: 50uF cap and a 100KOhm resistor are in series. You need to put the uF into F so 50uF is 0.000050F
t = 100,000 X 0.000050
t = 5Seconds
The formula finds the vaule for one TC (time constant). There are 5 TC in the cycle so you 5 X 5 = 25 seconds total time. One TC is equal to 63.2% of the full value. Now this is neat. If you have a supply of 100V the cap charges a total of 63.2V.
CT 1 You take 100 X 0.632 = 63.2V
CT 2 Take 63.2 X 0.632 = 23.2576 add it to 63.2 = 86.4V
Ect... Keep going after 4 TC you get 98.2V so basically 100V by the 5th. That is the way TC work.
I know sometimes you have a Cap but want to know what resistor to put with it for a desired time. The formula is:
R = t/C
R = 0.04s/100 X 100-12F
R = 400MOhm
If you want to know the Cap.
C = t/R
I've used these many times to get the desired result. Hope that help you out!
K
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pebe
Nobel Prize Winner
United Kingdom
1078 Posts |
Posted - Feb 06 2007 : 5:08:43 PM
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Binary,
By 'academic' I meant were you doing the excercise just for the sake of doing it to prove a point.
I've looked at the site you give but cannot see a schematic of what you are trying to do, so I can't make any suggestions.
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Binary 1011001101
Nobel Prize Winner
United Kingdom
569 Posts |
Posted - Feb 07 2007 : 02:38:10 AM
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Thanks for the formulas, ill try to get my head round them!
I am doing this exercise because... hmmmmm ummmm I saw other people do it so I thought I will give it a try...
Ive got the schematic here http://i96.photobucket.com/albums/l178/binary10101/Coilgun.jpg
C3 is the capacitor bank T1,T2,T3 are 24v wired in series. |
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pebe
Nobel Prize Winner
United Kingdom
1078 Posts |
Posted - Feb 07 2007 : 04:41:09 AM
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| Are the bunch of components operated by SW3 drawn correctly. If so, can you explain what are the components marked with a backward 'D', and what is supposed to happen? |
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Binary 1011001101
Nobel Prize Winner
United Kingdom
569 Posts |
Posted - Feb 07 2007 : 07:54:55 AM
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The components marked with the backward D are SCRs, I forgot to lable them.
SW3 is the chaging relay, that chages C3
when SW5 is pressed it shorts the capacitor bank with L1 which is the coil.
If you want more detail just say. |
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Physics
