needed

  1. D

    Kinematics IB question, explanation needed

    Could someone please explain (c) and (d) in the question below and attachment. When I tried, I got 735 N, but that isn't the right answer. Thanks in advance for the help. 51 The diagram shows a person in an elevator pulling on a rope that goes over a pulley and is attached to the top of...
  2. D

    statics problem, help needed

    Hello Problem description: determine the lenght of h with respect to b so that the water flows. ive gotten as far as come up with an equation for the sum of moments and it goes as follows: bh*1/2b-1/2hb*1/3b=0 the answer is wrong and i dont know why. moment arm on the b is 1/2b and...
  3. A

    How much mass needed to cool down liquid?

    https://imgur.com/a/a7yJtFh It's question 5. Could someone push me in the right direction here. Idk what's up. Is there a part along the way where I've got it wrong or is it right from the beginning lol? Thanks for any help (Bigsmile)
  4. K

    Help needed for thermodynamics questions

    Finding the correct 'Length' of a pipe? Hello again, i've been struggling with question a) for a few days now and I have now reached a cross-road. The problem in itself lays in the framing of the question. So if you would take a look at the question in the attached document you will see that my...
  5. C

    what magnitude of uniform magnetic field are needed

    $\textsf{ You wish to hit a target from several meters away with a charged coin having a mass of $4.2 g$ and charge of $+2400 \, \mu C$}\\$ $\textsf{The coin is given an initial velocity of $14.0 \, m/s$, and a downward uniform electric field strenght $29 \, N/C$ exists throuhout the...
  6. D

    Help needed for thermo efficiency

    Still working on my physics nearly done, I need help with the calculations of heat transfer in a room of 10x10x5high in metres, with the use of heat pump, and gas furnace. The purpose of the calculation is to determine thermal efficiency ..plus energy required to heat the room from 0 to 25 C, I...
  7. A

    Help is needed

    http://physicshelpforum.com/attachment.php?attachmentid=1915&stc=1&d=1497188341 Can you tell me if I wrote the equations correctly?
  8. A

    Help is needed

    http://physicshelpforum.com/attachment.php?attachmentid=1914&stc=1&d=1497188207 I have an exam this week and i don't know if i represented the forces correctly
  9. A

    Simple question help needed please

    Firstly can I appologies for asking such a simple question, I last 'studied' physics thirty years ago at school and that was at a pre GCSE level and I was by no means a scholar. Would one get a stronger magnetic 'pull' from a magnet if the ferrous metal it was attracted to was larger in size...
  10. D

    Help needed deriving acceleration and velocity components

    Hi all, I'm struggling to complete derivations for the system described in the attachment. I've never been good at coordinate transformations so could really use some help with the steps. Would like to derive the equations as listed in the attachment. Thanks very much in advance!
  11. G

    Fumehood exhaust Venturi design help needed please

    Hi I have a fumehood and would like to know the most efficient way to use my fan. I'm in the belief a Venturi design is best but some one might have a better idea. Please look at my crude drawing and try tio solve it for me please. The equations involved in solving this are beyound me...
  12. C

    Basic problem, quick help needed

    Hi, really simple but my head is fried and i can't get my head around this. Would the guage reading at A be as simple as atmospheric pressure+pgh for (ii)?
  13. S

    Thermodynamics equation needed

    Hello, I'm doing a solar panel self-cooling and self-cleaning project. I'm trying to use fins to help cool the solar panel. What equation should I be using to determine the amount of fins needed to dissipate heat and how much heat is dissipated? The solar panel I'm trying to use...
  14. J

    What force is needed to turn the Earth Pole-over Pole. Eg. UK now on Equator?

    Specifically, if someone could specify the Joules energy required to force the Earth to slowly rotate the poles end-to-end by say 1 degrees rotation, and by 5 degrees. To be clear I mean to literally rotate the Earth (both poles in opposite directions), say Singapore will therefore be below the...
  15. I

    Projectile Motion Question (help needed)

    Here's the question: You can throw a stone to a max height h. What is the maximum horizontal distance over level ground you can throw the stone? it leaves your hand at 1.5m above ground. I know how to do this question without the 1.5m (My book has a lovely example problem) with the 1.5m...
  16. L

    minimum force needed

    is part C lack of information ? can someone give me a hint how to start ? for part a , -(1.35-0.95)(200cos60)-2(200sin60)=-386N(anticlockwise) for part b , -386.4/2 = 193N (in upward direction)
  17. M

    Heat exchanger energy equation and boundry conditions.. Help/advice needed

    Hello, I am a student currently working on my master thesis, the subject of which is the design and analysis of a heat exchanger. Because of some delays, bad luck and the calculations not leading where we (my promotor and me) hoped they would I am running a bit behind... The design part of...
  18. J

    Simple explanation needed

    Hi everybody out there. I have a simple problem one which I in fact solved fairly easily with a few assumptions. However looking back on it I find that I do not fully understand one facet of the problem and I am asking if anyone can give me a simple explanation to clear my confusion. The...
  19. A

    Question help needed

    Im attempting this question for an evening class im attending. First time poster so hope im posting in the right place. I'm not sure where I have gone wrong think its where I rearranged my formula to find steam output. Question attached below
  20. B

    Help needed

    Hi everybody i am not looking for the answer what i am looking for is the method of how i achieve the answer Air is heated from 18ºC and 300 kPa in a fixed volume of 0.9m3. The final pressure is 700 kPa. Calculate the (i) final temperature (ii) mass of the air Thanks