1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

True of False Questions X_x

  1. Sep 22, 2013 #1
    1. The problem statement, all variables and given/known data
    I only get one chance at getting these ALL right... Nazi teacher :P lol

    1. Two planes parallel to a third plane are parallel.
    True, planes take up a lot of space so this seems reasonable :P

    2. Two lines either intersect or are parallel.
    False, there is a lot of space for both of them i think

    3. Two planes perpendicular to a third plane are parallel.
    True Normal vectors perpendicular to a plane are parallel so I suspect this to be true


    4. Two planes perpendicular to a line are parallel.
    True, in my head i'm picturing a line on the xy axis. all the planes coming off of it are parallel.

    5. A plane and a line either intersect or are parallel.
    False, i'm imaging a line that is bound to the xy axis and a plane going past it without touching it.


    6. Two lines perpendicular to a plane are parallel
    True, picturing this in my head I believe they would have to be

    7. Two planes either intersect or are parallel.
    True, Planes are big and if they don't cross they must be parallel

    8. Two lines parallel to a third line are parallel.
    True, (a lot of my answers are true >.<) in my head it seems like they would have to be.... i hope these explanations aren't too vague lol

    9. Two lines perpendicular to a third line are parallel.
    TRUE!! they would be shooting off at the same direction...

    10. Two planes parallel to a line are parallel.
    idk... i want to say true again but i doubt all these are true

    11. Two lines parallel to a plane are parallel.
    False, I picture in my head a plane and then a line parallel to it on the xy axis and one on the zy axis

    3. The attempt at a solution
     
  2. jcsd
  3. Sep 22, 2013 #2

    Mark44

    Staff: Mentor

    Instead of a reason such as "planes take up a lot of space" think about the normals to the planes.
    Presumably you're working in three-dimensional space. In the plane, lines either intersect or are parallel. In space, can you come up with an example of lines that don't intersect and aren't parallel?
    Again, think about normals to the planes.
    There is no "xy" axis. Are you talking about the x-axis, y-axis, or x-y plane?
    A line in the x-y plane? How does the plane "go past" it? Can you describe what you're thinking more precisely?
    Think about direction vectors for the lines and a normal for the plane.
    Planes are "big"? In what sense? Your reason isn't very good.
    This and several others are very vague. T/F questions are pretty silly, IMO, as you can flip a coin and have a reasonable chance of getting the right answer. If you are graded on your reasoning, though, many of your reasons here would not get credit.
    No, this is false.
    This is false. For example, the vector <0, 0, 1> is parallel to both the x-z plane and the y-z plane, but these two planes aren't parallel to each other.
    Again, there is no x-y axis nor is there a y-z axis. These are planes.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: True of False Questions X_x
  1. True/false questions (Replies: 4)

Loading...