What are the Typical Derivatives in Mechanical and Electrical Components ?

Thread Starter

darkmasta

Joined Oct 25, 2009
8
Hello,

Can someone PLEASE give me a site or a list of typical derivative components ?

These include di/dt ,dv/dt, dx/dt ...etc

For example :

For example :

dq/dt = i

dx/dt = v

di/dt = ?? (do you know what di/dt is ? Im not sure)

dv/dt = a

d^2x/dt^2 = a

and etc..

I really need it for my studies .. A test is coming soon and I need to study for it ..

Thank you for your time,
Dm
 

someonesdad

Joined Jul 7, 2009
1,577
I think you're barking up the wrong tree -- you should learn the physical principles first and the basic math models will follow. Learning a bunch of formulas is meaningless and if that allows you to pass exams, then you're definitely in the wrong class -- your instructor should be teaching principles and using those principles to analyze and solve problems, not making you memorize dumb formulas -- that's what handbooks are for. Learn the principles and develop your intuition first.
 

Thread Starter

darkmasta

Joined Oct 25, 2009
8
Im sorry but I didnt say that I want to memorise them to pass exams ..

You are accusing me of that already ?

Sorry but I just wanted them to better understand the formulas ..

Inductance is v=L*di/dt ... I couldnt find what di/dt is, so I wanted to check online ..

Here is proof that im studying and not memorising ..


http://img39.imageshack.us/img39/6434/25102009093n.jpg


Do I really need to show all of this for what I asked for ? Im sorry to appear rude but I really hoped for a more helpful reply :S

Thank you,
Regards,
Dm
 

wr8y

Joined Sep 16, 2008
232
Well, the image you posted sure proved what you are doing! :cool:

Knowing this site, SOMEONE will come along with something that can help you. And I can't wait to see it.
 

Ratch

Joined Mar 20, 2007
1,068
wr8y,

Knowing this site, SOMEONE will come along with something that can help you. And I can't wait to see it.
You are right about that, wr8y.

darkmasta,

Can someone PLEASE give me a site or a list of typical derivative components ?

These include di/dt ,dv/dt, dx/dt ...etc
I assume you know what defines a derivative. You can make a derivative out of any two quantities as long as they have a mathematical relationship to each other. Some common derivatives have names like current, which is dq/dt. Some don't have names, just descriptions; like dv/dt and di/dt are just voltage change per time and current change per time. So you just make up the derivatives as you need them, as long as you follow the mathematical rules and physical reality. Same goes for integrals, i.e. speed = ∫d(acceleration)*dt .

Ratch
 

Thread Starter

darkmasta

Joined Oct 25, 2009
8
Thanks for the replies :)

Ratch, so you're saying that di/dt does not really mean the derivative of another quantity ? such as how dq/dt = current ?

I didnt know that, thank you :)

A class with 150+ students makes it hard for me to ask such a simple question, so I had to revert to the net ..

I am going to ask him anyway if there is a list of the common derivatives as well, just to make sure I study them all for my course ... I will need to know them for the future as well..
Do you have any idea where can I find such site or any reference ?

Thank you :)
 

Ratch

Joined Mar 20, 2007
1,068
darkmasta,

[Ratch, so you're saying that di/dt does not really mean the derivative of another quantity ? such as how dq/dt = current ?/QUOTE]

The di/dt has no name that I know of, but it is still a valid and useful quantity.

Do you have any idea where can I find such site or any reference ?
No, you just learn them by cerebral osmosis. If you need it, then you know of it.

Ratch
 
Top