Results 1 to 6 of 6

Thread: physics help needed

  1. Apr 7th, 2003, 12:46 AM #1
    goonbag
    goonbag is offline

    Thread Starter
    New Member
    Join Date
    Apr 2003
    Posts
    1

    Angry physics help needed

    mmm goonbags
    Last edited by goonbag; Apr 15th, 2003 at 07:28 PM.
    Reply With Quote Reply With Quote
  2. Apr 7th, 2003, 04:40 AM #2
    sql_lall
    sql_lall is offline
    Fanatic Member sql_lall's Avatar
    Join Date
    Jul 2002
    Location
    Up Above (i.e. AUS)
    Posts
    571

    Talking Right.

    Ok, i'm not sure, but i think (a) can be done with calculus.

    Because: Velocity is the rate of change of displacement.

    Displacement = (-4j)t^2 + (3i)t +(2k)
    Change in Displacement = (-8j)t + 3i
    => velocity at time t=2 = 3i -16j
    However, i'm not too sure about this, as i haven't done 3d vectors before.

    Oh, and by "What is the the unit vector in the direction of the x axis" i'm not sure what you mean, isn't this just i??
    sql_lall
    Reply With Quote Reply With Quote
  3. Apr 7th, 2003, 06:18 AM #3
    Doctor Luz
    Doctor Luz is offline
    New Member
    Join Date
    Apr 2003
    Location
    Beyond Juslibol
    Posts
    9
    Yes.

    v=dr /dt=3i -8tj

    if t=2 v=3i -16j

    I don't understand your second question.
    Reply With Quote Reply With Quote
  4. Apr 7th, 2003, 12:52 PM #4
    TheAlchemist
    TheAlchemist is offline
    Addicted Member TheAlchemist's Avatar
    Join Date
    Jan 2003
    Location
    Dar-esSalaam,Tanzania
    Posts
    139
    hey guys,
    io think by the second question he's asking us to find the component of x of the position vector when t =2, so
    r = (3*2)i - (4 * 22)j + 2k

    r = 6i - 16j +2k

    therefore x component = 6

    i think this is right.
    One thing that sustains me through life is the conciousness of the immense inferiority of everyone else
    --Oscar Wilde
    Reply With Quote Reply With Quote
  6. Apr 8th, 2003, 07:23 AM #5
    kedaman
    kedaman is offline
    transcendental analytic kedaman's Avatar
    Join Date
    Mar 2000
    Location
    0x002F2EA8
    Posts
    7,221
    on the other hand the unit vector in the direction of the x axis is i, right?
    Use
    writing software in C++ is like driving rivets into steel beam with a toothpick.
    writing haskell makes your life easier:
    reverse (p (6*9)) where p x|x==0=""|True=chr (48+z): p y where (y,z)=divMod x 13
    To throw away OOP for low level languages is myopia, to keep OOP is hyperopia. To throw away OOP for a high level language is insight.
    Reply With Quote Reply With Quote
  7. Apr 9th, 2003, 02:44 PM #6
    marnitzg
    marnitzg is offline
    Hyperactive Member marnitzg's Avatar
    Join Date
    Oct 2000
    Location
    South Africa
    Posts
    372
    umm, i get (6/Sqrt(296))i
    ???
    Been a while but don't you have to divide by the norm to get the unit vector?
    Reply With Quote Reply With Quote
« Previous Thread | Next Thread »

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Forum Rules


Click Here to Expand Forum to Full Width