Recent content by 5carola5

  1. 5

    Heating up a wire with current

    wow, relax, I have got someone helping me with this (someone who know his stuff) and I am not going to use a 1mm wire (duh). I just wanted to know the formula's as a start =). Thanks a lot for them =)
  2. 5

    Heating up a wire with current

    @Matterwave: I was forgetting the heatcapacity. Not the heat capacity of copper but just that it was there at all. I was just looking at it like I have this and this and I know I can get to this but how again? Thanks so much! I can move on now and see what I get with the formula's you gave me...
  3. 5

    Heating up a wire with current

    thanks for the answer But in how much heat? Do you know some kind of formula (or have some idea to get it) to calculate the amound of heat (or temperature) that the wire would get in an amound of time. I would like to be able to calculate say how much my wire would heat up in 15 min or half an...
  4. 5

    Heating up a wire with current

    I have a question about an object heating up when electricity is applied. When putting electricity (say 10 to 15 A) trough a wire the wire will heat up because of it's resistance for electricity, right? But does anyone know how to do calculations on this? Like how to calculate how warm the...
  5. 5

    Fining the force constant of a spring

    when I type it in my calculator I get: (9,09 * 9,81) / (4,18^(-2)) = 1 558,06458 If that is the right answer than you just made a typo, if it's not then I also don't know:P
  6. 5

    Record travel along a straight path

    Can't you do the same for leg 3 as you did for leg 1? As they are pretty much the same, only the acceleration is now the other way around.
  7. 5

    Finding the Overall heat transfer coefficient

    Thanks so much for the answer. I will think about the thinks you said. Just for the record, we are not actually going to make the heat exchanger, we're just pretending. As for the overall heat transfer coefficient; for this part of the assignment we don't need to calculate that one jet (that...
  8. 5

    Finding the Overall heat transfer coefficient

    Yes it is an annular flow heat exchanger. As a did say; it's a counterflow one. Yes we can select if we want counterflow or co-current, but for this assinment we need to select counterflow, we can chance the volumeflux (I really hope it's called like that in English) and the temperature. The...
  9. 5

    Finding the Overall heat transfer coefficient

    Homework Statement We are having a fictive, non existing heat exchanger with the following parameters: Outer tube diameters: 20 & 12 mm Wall thickness inner tube: 1mm, outer tube; 2 mm flow area hot side: 0.0226m2, cold side; 0.0272 m2 The heatexchanger is going to cool some hot...
  10. 5

    How the find the temp of the middle plate

    Oke this is going to sound stupid but oke: What is a flux equation? My textbook (three sheets of paper home made by the teacher) is not saying anything about them... ^^'
  11. 5

    How the find the temp of the middle plate

    I did... didn't work out for me...
  12. 5

    How the find the temp of the middle plate

    Homework Statement We are having two the same metal plates. Plate one is having a temp of 127 degree celsius and plate two is 27 degrees celsius. Then a third plate, the same as the other two, is paced in the middle. What is his temperature? Homework Equations Don't really know. Maybe...
  13. 5

    Calculating Heat Flow Ratio of Two Water Tanks

    aaaah I forgot ^^' ((373^4) - (273^4)) / ((273^4) - (283^4)) = -16,1... Oke thanks a lot ^^" That was pretty stupit of me... But I will not do that wrong again for quite some time :P thanks again:)
  14. 5

    Calculating Heat Flow Ratio of Two Water Tanks

    I don't really know extally, can try to do it in Kelvin as the last time I did it in celsius... let's see. then it becomes: (373^4) / (283^4) = 3,018. That's also not alright, so it must be something else. Might be a total differend formula, I really don't know...
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