1. Hey Guest! Check out the 3 MCAT Study Plan Options listed in the 'stickies' area at the top of the forums (BoomBoom, SN2ed, and MCATJelly). Let us know which you like best.

    Also, we now offer a MCAT Test-Prep Exhibitions Forum where you can ask questions directly from the test-prep services.
    Dismiss Notice
  2. Dismiss Notice

Mcat Form Bt Discussion

Discussion in 'MCAT Discussions' started by qweewq11, Aug 17, 2002.

  1. qweewq11

    qweewq11 Smiley orgy organizer

    Joined:
    Jun 22, 2002
    Messages:
    942
    Likes Received:
    13
    Ok let's talk about form BT!

    1) EKG: Why did the guy's T wave disappear when he was on the treadmill? I said it was b/c it was smothered by the other waves.

    2) Mesoderm was radioactively labeled. Which organ was not radioactive in the adult?
    Choices: Kidney, lungs, heart, bone.
     
  2. Thread continues after this sponsor message. SDN Members do not see this ad.

  3. nero

    nero Senior Member

    Joined:
    Oct 15, 2000
    Messages:
    365
    Likes Received:
    1
    for #1 i put the one about it being overlapped by the other peaks
    .........its the only one that made logical sense..........caues the ventricles would not quit contracting and then the other two were kinda weird.

    for the mesoderm i believe the lungs are not mesoderm, but are endoderm...............

    nero
     
  4. qweewq11

    qweewq11 Smiley orgy organizer

    Joined:
    Jun 22, 2002
    Messages:
    942
    Likes Received:
    13
    1) And when the guy on the EKG was exercising, what did his atrial blood pressure do (was it atrial? or aortic? I forgot...)

    Same, lower, higher, ..... and I think "cannot be determined."

    2) The Q with that weird drug that had binding strengths relative to wild type and defective type in the blood....researchers want something that binds strongly b/c:

    I said it was b/c it competed for sites better, but the other option that sounded good was "b/c it is more stable in the blood" or something to that effect.

    3) Melanocytes/albinos question. The W mice have white skin but black eyes b/c:
    I said it was b/c they don't have migratory neural crest cells.

    4) Ochem question abou ortho meta para substituted nitrobenzene. NMR that would confirm meta position:
    I said a 1H singlet.

    5) Chemical shift of protons of acetaldehyde in CDCl3: 3H singlet at ~9.5, 1H singlet at .... some low number, 2.5 or so I think.
     
  5. qweewq11

    qweewq11 Smiley orgy organizer

    Joined:
    Jun 22, 2002
    Messages:
    942
    Likes Received:
    13
    ok b/c i have no life whatsoever and am too tired to party I will post some more Qs that I remember offhand, even though i got em right.

    Physics: Soemthing about a ray of light from the center of the sun moving like 6E7 light years thru the dense atmosphere of the sun until it exited the sun (yeah yeah, I'm butchering the questions I know). The question was "What was the angular velocity." This one threw me for a loop since I thought i'd need to know something about rotation, but there wasn't any rotation given, so I just wrote the obvious choice, which was distance / speed of light which yielded [some really big number] km/yr.

    Ochem: some hendersson hasselbach equation...given ph of blood and pka of a drug (drug A and B effect on osteoclasts or something). Find ratio of conj. acid to base. I said it was 10^5:1, since initial pka was around 2.4 and blood was 7.4.

    Another osteoclast/osteoblast/drug trial Q: Drug A and B was applied to 4E4 osteoclasts and 2E4 osteoblasts. The effectiveness was like 100:5, and the Q asked how many receptors or something we would have exptected with drug A and B respectively. I am fuzy on this question so if anyone wants to pick it up from here, go ahead. My answer was 4E7 and 1E5 respectively (or may have been othe way around, I forgot).
     
  6. qweewq11

    qweewq11 Smiley orgy organizer

    Joined:
    Jun 22, 2002
    Messages:
    942
    Likes Received:
    13
    Physics: There was that one with the fluids in the cylinders wit hthe gauge in the middle.

    1) Why was one side higher than the other:
    I said b'/c the air pressure in the closed end was higher than the pressure in the open end.

    2) Something about what would happen to h20 level if G was larger. I can't remember much else about the Q.
     
  7. qweewq11

    qweewq11 Smiley orgy organizer

    Joined:
    Jun 22, 2002
    Messages:
    942
    Likes Received:
    13
    Would have been nicer if i had remembered the answers! :laugh: +pissed+
     
  8. qweewq11

    qweewq11 Smiley orgy organizer

    Joined:
    Jun 22, 2002
    Messages:
    942
    Likes Received:
    13
    Ya I got 13s on my practice test psci but this psci kicked my butt. I like kinematics, and my psci was all fluids and electrostatics! (but surprisingly, no magnetism)
     
  9. qweewq11

    qweewq11 Smiley orgy organizer

    Joined:
    Jun 22, 2002
    Messages:
    942
    Likes Received:
    13
    hmm let's compile some more questions. Heck maybe Kaplan will pay me for remembering all the MCAT q's!:

    Albinos/W mice: Albinos all white, incl. eyes b/c of bad tyrokinase. What products are not in cell:
    Ans: There is tyrosine but not [some weirdly named intermediate....] and melanin, since the tyrokinase can't catalyze it.

    Between what part of PQRST waves is the most sodium entering heart cells
    Ans: Between Q and S.

    Random verbal:
    Birds on skellig michael are like:
    ans: Penguins to antarctic explorers.

    If the legend of the Nordic king and skellig michael is true, what would make sense:
    Ans: The king was converted by the Father superior.

    Back to science:
    w/o iodine, thyroid gets too big b/c:
    Ans: No TSH negative feedback on TRH, so more and more TRH which overstrimulates thyroid.

    For hypothalamo hypophyseal portal system to function, there must be:
    Ans: TRH receptors in thyroid and thyroid hormone receptors in hypothalamus (I think I butchered the question, but u get the idea)

    A tumor where would result in too much [some hormone I forgot] being produced:
    Ans: Anterior pituitary.
     
  10. qweewq11

    qweewq11 Smiley orgy organizer

    Joined:
    Jun 22, 2002
    Messages:
    942
    Likes Received:
    13
    + and - fungi do what:
    Ans: sexually reproduce.

    Lotsa Lewis acid and base qs.

    Ionization energies of some compound are 1 ~500, 2 ~4500, 3rd ~14000. Element is most likely:
    Ans: Some alkaline earth metal, I forgot which one.

    Which as lowest entropy: ice, h20, steam, etc.
    Ans: ice.

    Ochem: nitrogen in some compound I forgot is hybrizized:
    ans: sp2.

    Which fats are liquids at 20 C
    ans: All the ones with melting pts below 20....linoleic, linolic, and oleic I think they were, but I can't remember 4sure.

    Which fat would not Pt+H2 to form stearic acid:
    The one with only 16 C's, not 18Cs, and a double bond.
     
  11. qweewq11

    qweewq11 Smiley orgy organizer

    Joined:
    Jun 22, 2002
    Messages:
    942
    Likes Received:
    13
    Psci: Rolling an object down a ramp with angle theta to horizontal alters g by a factor of:
    Ans: cos theta.

    ADH acts where:
    ans: collecting duct.

    Some quesiton about LCDs and index of refrac and polarization.

    for pixel to be off, glass must be polarized at what angle?
    Ans: 90 degrees.
     
  12. qweewq11

    qweewq11 Smiley orgy organizer

    Joined:
    Jun 22, 2002
    Messages:
    942
    Likes Received:
    13
    Temperature of some stuff that is refluxing:
    Ans: Same as boiling pt.
     
  13. Jugador75

    Jugador75 Senior Member

    Joined:
    Jan 8, 2002
    Messages:
    149
    Likes Received:
    0
    I didnt take the mcat yesterday, but if pH is 7.4 and pKa is 2.4, and they ask for ratio of conjugate ACID to base, then it would be the reciprical of 10^5, since the normal henderson hasselback equation has the base in the numerator and the acid in the denominator. I don't know how the question was phrased.
     
  14. qweewq11

    qweewq11 Smiley orgy organizer

    Joined:
    Jun 22, 2002
    Messages:
    942
    Likes Received:
    13
    oops, quite right. I had the order backwards, but it was the only answer choice w/ 10^5 and 1.
     
  15. Jugador75

    Jugador75 Senior Member

    Joined:
    Jan 8, 2002
    Messages:
    149
    Likes Received:
    0
    There was a question on fungi reproduction? I thought plants were not fair game??
     
  16. Thread continues after this sponsor message. SDN Members do not see this ad.

  17. qweewq11

    qweewq11 Smiley orgy organizer

    Joined:
    Jun 22, 2002
    Messages:
    942
    Likes Received:
    13
    for some reason I keep seeing one fungi question on all the aamc tests. Never one on plants, just on fungi. Odd.
     
  18. Biffer

    Biffer The good times doc

    Joined:
    Dec 21, 2001
    Messages:
    328
    Likes Received:
    0
    jugador,
    nice. the answer was 10^5, at least thats what I circled. The fungi question was very ambigously worded--Fungi reproduce by two means: Budding and Sexual reproduction..so, what is the relationship between these two modes? I didn't know and didn't remember reviewing the effect one has on the other. can anyone clarify? (Does one inhibit the other--thats what i chose..)

    later,
    biffer
     
  19. Jugador75

    Jugador75 Senior Member

    Joined:
    Jan 8, 2002
    Messages:
    149
    Likes Received:
    0
    Biffer, I'm sorry to hear that you put the incorrect answer to that question. I hope that doesnt effect your 41+. What the hell man? You reply to my SDN posts but you won't call me or give me your phone number? What's your deal?

    I'm sorry I screwed your girlfriend, but it only happened ONCE. (well, twice if you include that time in the bathroom at your parent's house....but that was in the ass so it shouldnt count)
     
  20. SuzyQ

    SuzyQ Senior Member

    Joined:
    May 3, 2002
    Messages:
    610
    Likes Received:
    0
    Hey...i got pretty much the same answers as your guys except for the nitrogen hybridizations.....wouldnt it have been sp3 because it had 3 H's attached and then it was attached to something else? I dont know...that was just my thinking
     
  21. nero

    nero Senior Member

    Joined:
    Oct 15, 2000
    Messages:
    365
    Likes Received:
    1
    i got the same first verbal as you............

    the second verbal i wasn't sure if that made sense or the attack one, becasue the way the question was worded, said what could you infer happened initally before he was king.......and since it said initally, i assumed it meant he attacked..

    that tumor one was about cortisol and i put adrenal cortex..(i think)....was the option adrenal medulla or adrenal cortex?

    nero
     
  22. spanky

    spanky Member

    Joined:
    Sep 2, 2001
    Messages:
    93
    Likes Received:
    0
    Question on the section on fatty acids passage. Which of the fatty acids are soluble in water? I said none because of the dominance of the nonpolar carbon chains. What was the answer for that one???
     

  23. Yup, i think you are right =D good job.

    For the verbal question about birds on the island...why was the answer the penguin one...
     
  24. spanky

    spanky Member

    Joined:
    Sep 2, 2001
    Messages:
    93
    Likes Received:
    0
    In the passage about the monks, it was stated that the island was only environmently friendly for birds not humans. This would be comparable to penguins inhabiting anartica, which is one of their natural habitats, but the environment of anartica is not conducive to human habitation.

    How did you guys answer the question inferring the past behavior of King Olav? I narrowed it down to: he asked for spirital guidance from the abbot of the monastary or he had previously raided the island looking for riches. I ended up choosing the former answer because he could have converted based on guidance from someone other than the abbot. I would welcome any alternative explanations.

    Why did people come to the island to kiss the rock? Since the passage said that penitents came to the island, I chose the answer that said it was to atone for their sins. The other possible answer was that it was some sort of rite to enter the religious order. Which was the correct answer?
     
  25. nero

    nero Senior Member

    Joined:
    Oct 15, 2000
    Messages:
    365
    Likes Received:
    1

    i put to enter the religious order.......the last paragraph of the passage hinted soemthing toward entering the monastery........but it could also be to get rid of their sins......

    nero
     
  26. Mimicat

    Mimicat Senior Member

    Joined:
    Aug 16, 2001
    Messages:
    112
    Likes Received:
    0
    On the island monestary passage, why did they choose the island as the location? I couldn't decide between "it provided the best opportunity for suffering" and "it was isolated from the distractions of modern life" ... I think I put the second one b/c it said somewhere else in the passage that they chose the desert because it was far away from others/tempatation, or something like that.

    I agree with the Penguins in the antartics choice, and that visitors kissed the rock to ask for penitance.

    The ques about King Olaf's past behavior, I put that he came looking for riches, b/c it said that after he was converted, he stopped his "pillaging" (thought that was a good clue, but I may be wrong).

    The ques about why the island would only have about 12 monks on it, I put b/c there was lack of space for them, but I was torn between that and the possibility of running out of food and water. I think the first is right, because the second could be imagined, but was never directly referred to or even inferred in the passage. The passage mentioned that the rock was so steep it was mostly inhabitable for humans, so I took that to mean there wasn't enough flat space for more than 12.

    Biffer, on the fungi ques, I think I put the same as you - that the two fungi together would result in one inhibiting the other ( I can't remember the details, but I think it was really ambiguous wording too)

    It's nice to rethink some of these questions - thanks guys.


    :love:
     
  27. qweewq11

    qweewq11 Smiley orgy organizer

    Joined:
    Jun 22, 2002
    Messages:
    942
    Likes Received:
    13
    Yup, dominance of the nonpolar carbons. The distractor was that one had a cooh group on it, but that wouldn't matter since the olefin chain was so long.

    Another question:

    I think it was the lac operon one. Why is one site less susceptible to mutation than the other site?
     
  28. qweewq11

    qweewq11 Smiley orgy organizer

    Joined:
    Jun 22, 2002
    Messages:
    942
    Likes Received:
    13
    Physics: there was one problem about calculating hte velocity of an electron that was accelerated thru a potential difference. I was running out of time so I had to make an educated guess, but I chose the only one with a ^1/2 power in it, since the calculation would have involved equating 1/2mv^2 to PE.

    Was this rite? I don't remember much about the question 'cause I was rushing.
     
  29. nero

    nero Senior Member

    Joined:
    Oct 15, 2000
    Messages:
    365
    Likes Received:
    1
    i put the shorter sequence......i didn't think the I binding would make O less susceptible to mutation............if its shorter, mutations are probably less frequent...........

    did anybody get the mouse one with color?.........why is the odd color less seldom found?.......i put cause those genes decrease fitness..........the otehr one was that it could get diluted........but i figured how would any new genes evolve becuase the wild type could dilute everything with that reasoning......any thoughts?

    nero
     
  30. qweewq11

    qweewq11 Smiley orgy organizer

    Joined:
    Jun 22, 2002
    Messages:
    942
    Likes Received:
    13
    Verbal: Manet's Foliere Begere (sp?)

    1) Was one of the answers something about how he was concerned about his legacy and impact on future artists?

    2)If research had shown the painting was made 2 decades earlier than thought, which would have to be true:
    Ans: He would have to have been diagnosed with a terminal illness.
     
  31. qweewq11

    qweewq11 Smiley orgy organizer

    Joined:
    Jun 22, 2002
    Messages:
    942
    Likes Received:
    13
    Man I posted like 40 questions but I've only seen like 10 get discussed. I will organize them so that maybe we will get them all answered.

    1) EKG: Why did the guy's T wave disappear when he was on the treadmill? I said it was b/c it was smothered by the other waves.

    2) Mesoderm was radioactively labeled. Which organ was not radioactive in the adult?
    Choices: Kidney, lungs, heart, bone.

    3) And when the guy on the EKG was exercising, what did his atrial blood pressure do (was it atrial? or aortic? I forgot...)

    Same, lower, higher, ..... and I think "cannot be determined."

    4) The Q with that weird modified protein that had binding strengths relative to wild type and defective type in the blood....researchers want something that binds strongly b/c:

    I said it was b/c it competed for sites better, but the other option that sounded good was "b/c it is more stable in the blood" or something to that effect.

    5) Melanocytes/albinos question. The W mice have white skin but black eyes b/c:
    I said it was b/c they don't have migratory neural crest cells.

    6) Ochem question abou ortho meta para substituted nitrobenzene. NMR that would confirm meta position:
    I said a 1H singlet.

    7) Chemical shift of protons of acetaldehyde in CDCl3: 3H singlet at ~9.5, 1H singlet at .... some low number, 2.5 or so I think.

    8) Physics: Soemthing about a ray of light from the center of the sun moving like 6E7 light years thru the dense atmosphere of the sun until it exited the sun (yeah yeah, I'm butchering the questions I know). The question was "What was the angular velocity." This one threw me for a loop since I thought i'd need to know something about rotation, but there wasn't any rotation given, so I just wrote the obvious choice, which was distance / speed of light which yielded [some really big number] km/yr.

    9) Ochem: some hendersson hasselbach equation...given ph of blood and pka of a drug (drug A and B effect on osteoclasts or something). Find ratio of conj. acid to base. I said it was 10^5:1, since initial pka was around 2.4 and blood was 7.4.

    10) Another osteoclast/osteoblast/drug trial Q: Drug A and B was applied to 4E4 osteoclasts and 2E4 osteoblasts. The effectiveness was like 100:5, and the Q asked how many receptors or something we would have exptected with drug A and B respectively. I am fuzy on this question so if anyone wants to pick it up from here, go ahead. My answer was 4E7 and 1E5 respectively (or may have been othe way around, I forgot).

    11) Physics: There was that one with the fluids in the cylinders wit hthe gauge in the middle. Why was one side higher than the other:
    I said b'/c the air pressure in the closed end was higher than the pressure in the open end.

    12) Physics: Same fluids Q: Something about what would happen to h20 level if G was larger. I can't remember much else about the Q.

    13) Killing tumors w/ radioactive Cobalt vs/ Xrays: amount of radiation that makes it thru a 20cm person.
    Ans: I think I put 1/2.

    14) Same tumors Q. Why is Cobalt better than Xray:
    Ans: B/c it can penetrate further.

    15) Albinos/W mice: Albinos all white, incl. eyes b/c of bad tyrokinase. What products are not in cell:
    Ans: There is tyrosine but not [some weirdly named intermediate....] and melanin, since the tyrokinase can't catalyze it.

    16) Between what part of PQRST waves is the most sodium entering heart cells
    Ans: Between Q and S.

    17) Random verbal:
    Birds on skellig michael are like:
    ans: Penguins to antarctic explorers.

    18) If the legend of the Nordic king and skellig michael is true, what would make sense:
    Ans: The king was converted by the Father superior.

    19) Back to science:
    w/o iodine, thyroid gets too big b/c:
    Ans: No TSH negative feedback on TRH, so more and more TRH which overstrimulates thyroid.

    20) For hypothalamo hypophyseal portal system to function, there must be:
    Ans: TRH receptors in thyroid and thyroid hormone receptors in hypothalamus (I think I butchered the question, but u get the idea)

    21) A tumor where would result in too much [some hormone I forgot] being produced:
    Ans: Anterior pituitary.

    22) + and - fungi do what:
    Ans: sexually reproduce.

    23) Ochem: nitrogen in some compound I forgot is hybrizized:
    ans: sp2.

    24) Which fats are liquids at 20 C
    ans: All the ones with melting pts below 20....linoleic, linolic, and oleic I think they were, but I can't remember 4sure.

    25) Psci: Rolling an object down a ramp with angle theta to horizontal alters g by a factor of:
    Ans: cos theta.

    26) ADH acts where:
    ans: collecting duct.

    27) Some quesiton about LCDs and index of refrac and polarization. for pixel to be off, glass must be polarized at what angle?
    Ans: 90 degrees.

    28) Calculate n value vs. vacuum of some compound where light moves at 2.5E8 m/s. Ans: 1.2

    29) Various hydrocarbons with varying branching. Which has highest BP.
    Ans: the one that was least branched

    30) Which fat is miscible with H20:
    Ans: None, b/c hydrocarbon tail is dominant.

    31) Temperature of some stuff that is refluxing:
    Ans: Same as boiling pt.

    32) Ionization energies of some compound are 1 ~500, 2 ~4500, 3rd ~14000. Element is most likely:
    Ans: Some alkaline earth metal, I forgot which one.

    33) Which as lowest entropy: ice, h20, steam, etc.
    Ans: ice.

    34) I think it was the lac operon one. Why is one site less susceptible to mutation than the other site

    35) Physics: there was one problem about calculating hte velocity of an electron that was accelerated thru a potential difference. I was running out of time so I had to make an educated guess, but I chose the only one with a ^1/2 power in it, since the calculation would have involved equating 1/2mv^2 to PE.

    Was this rite? I don't remember much about the question 'cause I was rushing.

    36) Verbal: Manet's Foliere Begere (sp?) Was one of the answers something about how he was concerned about his legacy and impact on future artists?

    37) If research had shown the painting was made 2 decades earlier than thought, which would have to be true:
    Ans: He would have to have been diagnosed with a terminal illness
     
  32. judoka

    judoka Banned
    Banned

    Joined:
    Jul 31, 2002
    Messages:
    78
    Likes Received:
    0
    3. for blood presssure, shouldn't it go up? with higher heartrate, all things being the same?

    13. i put 2, the ratio was asked in a different order than the numbers were presented.

    14. i think because it concentrates better (it's effective range is right in the middle of a person).

    15. yeah, there is tyrosine

    37. i don't remember exactly, but i think the answer meant said something like he had to have started seeing his life from multiple perspectives early on (since the passage said he knew he was terminally sick for a long time)
     
  33. spanky

    spanky Member

    Joined:
    Sep 2, 2001
    Messages:
    93
    Likes Received:
    0
    okay, one more stupid question. In the bio section there was a passage about two different drugs which effect osteoclasts/osteoblasts. One question said that osteoclasts will hollow out the center of the bone and wanted to know how the new bone would be deposited in the remodeling. The choices were:
    1. New bone would form from the inside to the outside
    2. new bone would form from the outside to the inside.
    3. New bone would be laid down around central canals.
    4. new bone would be laid down nearest blood vessels first.

    The passage said the new bone must be deposited onto to old bone in order to have something to adhere to. Anybody have any ideas???? I said the bone would be formed from the outside to the inner portion of the canal, but that was just a guess.
     
  34. I guess I read that question wrong. Anyway I said that it would grow inner to outer. However I thought the question simply asked about how new bone was deposited. I totally missed the hollowing thing. Damn another question missed due to sleep deprivation. In fact I think I missed most of the questions posted here because I couldn't stay awake.

    Anyway your answer seems right.
     
  35. Mimicat

    Mimicat Senior Member

    Joined:
    Aug 16, 2001
    Messages:
    112
    Likes Received:
    0
    On the osteoclast ques, I also answered from the outside to the inside. I think that is right b/c if it is hollowed out on the inside and it needs old bone to grow onto, it would have to start on the outside and move in.
     
  36.  
  37. 25) I had a different answer, SIN THETA. The angle is from the horizontal. Sin 90 = 1, sin 0 = 0. If the ramp is straight up and down, then theta equals 90, and g * sin 90, or g. If the ramp is flat, then theta = 0, and g * sin theta = 0. It was a trick question, and unless I misinterpreted it, I believe the answer is SIN THETA.
     
  38. qweewq11

    qweewq11 Smiley orgy organizer

    Joined:
    Jun 22, 2002
    Messages:
    942
    Likes Received:
    13
    yup i think ure right. My friend told me that too.
     
  39. glomerulus

    glomerulus Junior Member

    Joined:
    Aug 6, 2002
    Messages:
    13
    Likes Received:
    0

    Yea. I think you're right too. I put cos theta, but then figured it out during lunch break. I'm pretty sure its sin theta.

    Also, about the question about birds on skelig michael, the answer I put has not been suggested by anyone yet, so I'm beginning to think I am wrong. We all agree on the fact that the passage implied that the monks were out of their natural habitat and living in a place only normally inhabitable by birds. But I think this statement was in the same paragraph talking about the height and difficulty of reaching skelig michael. So I said the birds statement was analogous to a "helicopter to a mountain climber" because a mountain climber reaches places that are normally only occupied by helicopters.

    Does anyone agree? or am i just off my rocker?
     
  40. Jonkst

    Jonkst Senior Member

    Joined:
    Mar 20, 2002
    Messages:
    209
    Likes Received:
    0
    I put the helicopter thing too, but I wasn't sure of it. I'm also not that great at verbal, so we'll see.
     
  41. I picked SIN THETA as well. I just rememberd EK saying to think sin theta when you have an incline plane.
     
  42. That is the exact same thought I had. At first I went with the penguin answer but it seemed way to easy and just screamed MCAT trap so I decided to come back to it. I was searching the paassage for another question when I came to the paragraph discussing height and difficulty of scaling the mountain. It just so happened that this was the only spot in the passage birds were mentioned. So the helicopter analogy makes sense in the context of that paragraph. The only paragraph mentioning birds.

    I can see the logic in both answers. Something tells me this will be one of those infamous "A is not wrong but C is the BEST answer" type of question.
     
  43. 8) I didn't even notice that it asked for the angular velocity. I did the same thing you did.

    9) Can't believe I missed this. I picked 5:1. Doh!

    11) That was my thinking

    12) Is that the quesiton where they place the apparatus in an accelerating elevator?

    16) Was that the region with the sharp spike?

    22) Do you remember what the other choices were?

    28) For some odd reason I remember that exact number.

    31) I always thought that heat of reflux was slightly above the bioling point. Well at least it was when I performed my orgo labs. Maybe thats why I always got a strange yield
    :laugh:
     
  44. nero

    nero Senior Member

    Joined:
    Oct 15, 2000
    Messages:
    365
    Likes Received:
    1
    was this the one about how much g would be reduced if a board was inclined at angle theta?>........if so, it actually was cos theta, not sin theta.......reason being: you assume the plan is the x axis and perpendicular to the plane is the y, and that g goes straight down.........when you draw the triangles and all that mess, it comes out to

    y = cos(theta) * g
    x = sin (theta) * g

    thus, g went from g to cos(theta)g...............it was reduced by a factor of cos (theta)

    that's the only way i've ever learned it......how did you figure sin?

    nero
     
  45. qweewq11

    qweewq11 Smiley orgy organizer

    Joined:
    Jun 22, 2002
    Messages:
    942
    Likes Received:
    13
    Was the question how much G was reduced? If so, sweeT! :clap:
     
  46. nero your method only works if your finding the resultant vector. g is scalar so it can not be found by the method you proposed.
     
  47. epignathus

    epignathus Junior Member

    Joined:
    Aug 18, 2002
    Messages:
    7
    Likes Received:
    0
    I didn't have this question but, if there was a choice that said g would not change I would have picked it since g doesn't change as you increase theta in an incline plane problem. If the question was how does the force pointing down the ramp change than I would have definitely said it decreases by a factor of sin theta since when you draw a free body diagram of all the forces on the object on the ramp the force down the ramp will be mg sin theta. mg cos theta will be contact force on the object.
     
  48. I agree, epi, but I think the question referred to the effect of g. At theta equals 0, g does not affect vertical motion.
     
  49. epignathus

    epignathus Junior Member

    Joined:
    Aug 18, 2002
    Messages:
    7
    Likes Received:
    0
    Correct sham, I did not have the question but from reading this post you could have definitely eliminated the two answer choice that involved sin 90 and sin 0.
     
  50. Jonkst

    Jonkst Senior Member

    Joined:
    Mar 20, 2002
    Messages:
    209
    Likes Received:
    0
    Well, I say sin theta, because if the angle of the ramp is 90 degrees, then the force of gravity is the same as normal. Cos 90 * g would = 0, and Sin 90 * g would = g, thus cos theta can't be the correct answer.

    Just my (and my roommate's) thoughts.
     
  51. nero

    nero Senior Member

    Joined:
    Oct 15, 2000
    Messages:
    365
    Likes Received:
    1
    its possible i'm wrong, but let me give you a problem that shows what i am proposing...............

    have a 30 degree angle ramp........a box of 10 kg is sliding down the ramp........what is its acceleration?.........(this will be due to gravity, BECAUSE i'm assuming the plane is the x-axis).....
    ASSUME NO FRICTION

    y = Normal Force - Force in Y direction
    x = Force in X direction

    since no movement in y direction:
    Normal = Force in Y = (cos30)(2)*(9.80)

    net force in X = (sin30)(2)(9.80) = (2)(a)

    Thus, you can solve from A.........this is straight out of my physcis book........i referred to 3 textbooks, and they all show it like this.........maybe i misread the question, tha'ts totally possible, but that's how i did it.........please enlighten me with your thoughts..............and correct me if i'm wrong........

    nero
     
  52. nero

    nero Senior Member

    Joined:
    Oct 15, 2000
    Messages:
    365
    Likes Received:
    1
    sorry, the 2s should be tens...........but you get the idea
     

Share This Page