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  1. L

    Basic Kinematics but I'm lost already

    At the Introductory Physics page where you posted this, there is a sticky at the top with different formulas in there. The link is <https://www.physicsforums.com/showthread.php?t=110015> and the formula you need is in there. It's in the second post that Doc Al posted under "General". You have...
  2. L

    Unit conversions help!

    317 hours, so 13.23 days. Like LowlyPion wrote... 5.25cm/min >> 315 cm/hour >> 3.15m/hour >> 0.31746 hr/m *(1000m) >> 317.46 hrs
  3. L

    Another Vector Question

    I believe so yes, that is what I had written down I think. I erased it but I think the angles I had were something like 68.198* and 26.565*
  4. L

    Another Vector Question

    It's been awhile since I've done any of this so somebody correct me if otherwise, but for west of north and for above the horizontal, you should not be using any distance as the hypotenuse. You will need two different triangles for each situation which you did, but the hypotenuse is not...
  5. L

    Simple question (I think )

    I had this problem or almost exact one back in high school. I found it easy to draw a picture, convert each vector into vertical and horizontal components...
  6. L

    Can you help me with NET DISPLACEMENT

    I think I get it, so you just calculated the hypotenuse of the triangle to be 60 as well? Which you didn't really need to do, but it's good to double check too. But yes, the tree I got was 30.02m >> 30m.
  7. L

    Can you help me with NET DISPLACEMENT

    You lost me here, what you mentioned prior to this is correct, then I got confused haha.
  8. L

    Can you help me with NET DISPLACEMENT

    You should get an answer of 30.02m which makes sense. If the shadow was the same as the height of the tree, that would suggest the angle is 45 (middle of 0-90). If the shadow was shorter than the tree, it would suggest the sun be more overtop of the tree, giving an angle closer to 90...
  9. L

    Can you help me with NET DISPLACEMENT

    Right, so you can use trig to find out the vertical length (line AB).
  10. L

    Can you help me with NET DISPLACEMENT

    That is right, but which angles are which, the 30 and 60 degree angles are where?
  11. L

    Can you help me with NET DISPLACEMENT

    You were right with the 52, I managed to put a crappy diagram there, but O is the sun, and that line ' - ' is the line that makes an angle of 30 degrees with the sun and the horizontal. So you say the angle should be in the corner A, but does the diagram help you to determine if you are right...
  12. L

    Can you help me with NET DISPLACEMENT

    o - - - - a - | - | - |__________________- b...
  13. L

    Can you help me with NET DISPLACEMENT

    Best way I find to do most questions like this is to draw pictures. So, this will end up being another triangle. So start with a tree, so a line going up, now then I drew the "shadow", so another line at the base of the tree going to the right. Now draw a line connecting the lines to...
  14. L

    Can you help me with NET DISPLACEMENT

    What did you get for the angle, I just want to see if you managed to get it. The angle where line D meets the horizontal? I'm hoping I did it right but you should get... 60.9 degrees... I think haha. You have to specify sometimes too on your diagram, or if you don't draw one with words. Now...
  15. L

    Can you help me with NET DISPLACEMENT

    Ah k, so you have 2 angles, one up where line D meets line A (vertical line) and we'll call this angle phi. You also have an angle where line D meets line B (horizontal line and we'll call this angle theta. Then a 90 degree angle where A meets B. Now you can use either angle phi or theta...
  16. L

    Can you help me with NET DISPLACEMENT

    Should be actually inverse tan I believe, along with the options of inverse cos, and inverse sin tan x = opposite/adjacent x = inv.tan (opp/adj) or... x = inv.cos (adj/hyp) or... x = inv.sin (opp/hyp)
  17. L

    Can you help me with NET DISPLACEMENT

    K, well i'll attempt this, draw the lines out on a paper. So draw one line from the start point (call this anything, I'll say C for explaining purposes) going to the right (east) 50 so let's say 5cm (even though in this case the drawing doesn't need to be exact). Now from there, draw a line...
  18. L

    Can you help me with NET DISPLACEMENT

    Basically ya, this is what I understood from the question. Hopefully that's what you wanted to do. Then you may* need to find the angle of displacement.
  19. L

    Can you help me with NET DISPLACEMENT

    Alright, well the vertical (positive or negative) would be the north and south ones. So let's say up (north) is positive. How far from the start position are you if you go 40 units south, then go 130 units north? (Ignore the east direction for now)
  20. L

    Can you help me with NET DISPLACEMENT

    I'm pretty out of it (tired), but I'll see what I can explain. From my understanding, this is dealing with vectors. Now it's hard to tell without a diagram or more knowledge of the question but for each direction, break it down into vertical and horizontal directions, then add up all the...
  21. L

    Annoying Logic Problems!

    Thats ok, I did it too Charmed. I still look at it every now and again, nothing really is jumping out at me though.
  22. L

    Annoying Logic Problems!

    CharmedQuark, I had what you had awhile ago, and thought I had it too... 19x5 does not equal 90, it gives 95. I am still lost on this as well haha.
  23. L

    Coefficient of Resistance for different metals.

    Thanks, shortly after I posted this I continued my search and found after typing in 'resistivity' I found mostly what I needed. Thanks berkeman.
  24. L

    Coefficient of Resistance for different metals.

    I was wondering if anyone knew of links to different websites that stated the coefficients of resistance for different metals. Mainly copper, and steel equipment. I am working in a mill and my supervisor asked me to find out these values. There is copper cable running as ground and...
  25. L

    Annoying Logic Problems!

    I recognized there was a pattern across, but at first didn't see there was a pattern going down. Number 13 is still bugging me a bit because it's something easy that is being overlooked I'm sure lol. If you get a response to that question you should let me know.
  26. L

    Annoying Logic Problems!

    Q1: Don't look at the rows, look to the columns. 9*9*9 gives what?
  27. L

    Voltage Drop (Three phase)

    This relates to this problem at the mill. There were readings taken from around the mill, on the PDCs and the breakers/equipment relating to each PDC. Now what I was looking for by posting this PDF attachment was anything odd from the readings. The only thing I really noticed was that in...
  28. L

    Voltage Drop (Three phase)

    Thanks again, in the 2nd part of that eqn. what is the X?
  29. L

    3d: Stoke's Theorem

    It's been a few years, so I am not really sure on this. Since it's oriented outwards, and there's 4 sides, the sides opposite each other would cancel each other out... (I think, but hopefully I get corrected if not) so the only surface that contributes is the top. Again, I would wait for...
  30. L

    Exponential equation help

    I found the same, you should get two real roots.
  31. L

    LN equation help

    A hint that may help is that with ln(x)... what value for x will give 0?
  32. L

    Voltage Drop (Three phase)

    Alright thanks. If I took a different approach and took the Ohms/(1000feet) value of the cable, and multiplied that by the length (600 ft) then multiply that by the current... would that be another method? = .6282 ohms/Kft * 600ft = .37692 ohms V = IR = 12A * .37692 ohms =...
  33. L

    Doors problem

    I read briefly over most of the posts, but from what I collected, you have to walk into and exit the house but can do this several times. You cannot use a door twice. Now if you have to enter, you must exit the house. Since there is 5 doors on the exterior of the house, you enter... exit...
  34. L

    Faraday's Laws

    Ya, I ignored that for a second when doing the calculation and got the same 0.005...V that you did, units cancelled. I'll wait for somebody else's reply because I am a bit confused now too haha. Do you have a correct answer for that?
  35. L

    Faraday's Laws

    It's been a long time since I've done any questions like this, but the equation "V=B/T * A * N" you use but you do not use the 'T' anywhere. You have "V = 8.15e-3 * (.218/2)^2 * pi * 18 turns" but unless I'm missing something, I don't see 'T' in there or a value of 'T' given in the question.
  36. L

    Voltage Drop (Three phase)

    AWG Dia-mils TPI Dia-mm Circ-mils Ohms/Kft Ft/Ohm Ft/Lb Ohms/Lb Lb/Kft *Amps MaxAmps 8 128.49 7.7828 3.2636 16509 0.6282 1591.8 20.011 0.0126 49.973 22.012 33.018 12 80.807 12.375 2.0525 6529.8 1.5883...
  37. L

    Voltage Drop (Three phase)

    I was just looking for some insight on this problem. It is not a homework problem, my boss just asked me to figure it out. Now, there is 120V supply, with 600 feet of cable (copper) running to a load, and 600 ft neutral coming back to the supply. Ignoring the resistance of the load, he asked...
  38. L

    Current resistor and time

    The way I did part A which works without needing the voltage is... I = Q/t... Q = I*t = 5A * 4min*(60s/1min) = 1200 Coul
  39. L

    Current resistor and time

    For the number of electrons per coulumb... h t t p : / / en.wikipedia.org/wiki/Electric_current That should help.
  40. L

    Kinetic theory and temperature in gases

    5k maybe? I just noticed that now...
  41. L

    GCSE Additional physics - NEED HELP =D

    50/50 chance there, Try again :P. If you have a smaller current flowing, less electrons (therefore: charge) would be flowing. Making sense... somewhat?
  42. L

    GCSE Additional physics - NEED HELP =D

    If the current is smaller (4mA < 1A), what does that say about what the charge passing? Would it be larger or smaller?
  43. L

    Kinetic theory and temperature in gases

    I'm fairly out of it because I'm pretty tired, but seems alright to me.
  44. L

    Intergration by substitution

    Haha no worries, least you found out where you went wrong
  45. L

    Intergration by substitution

    Should be... x = \frac{u^{2} + 1}{2} Shouldn't it? I managed to get the integral with 2u on the bottom and looking the same, but let me know how you're making out.
  46. L

    Using the superposition principle

    Is there a diagram or anything? May be helpful, at least for me.
  47. L

    What is a quadratic forumula

    Haha, I like your explanation on that one Borek
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