Results 1 to 5 of 5

Math Help - help with units maths

  1. #1
    Newbie
    Joined
    Aug 2007
    Posts
    4

    help with units maths

    hi

    im doing a course in complex maths for the building industry and have to pass this maths section before i go on. maths was a bad subject for me so now i need to learn. my biggest problem is notation such as one question is

    convert 39cm to km and answer in scientific notation

    would that be 100000cm = 1km therefore 39/100000=0.00039

    is that right

    and the one thats got me is

    a mass rests on an area of 80mm2 and exerts a force of 320 kg m/s2. express the pressure exerted on this area in kN/cm2

    i worked it out but not sure if im right

    so can you all help me out i will post more soon

    cheers dan
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Grand Panjandrum
    Joined
    Nov 2005
    From
    someplace
    Posts
    14,972
    Thanks
    4
    Quote Originally Posted by aadkeski View Post
    hi

    im doing a course in complex maths for the building industry and have to pass this maths section before i go on. maths was a bad subject for me so now i need to learn. my biggest problem is notation such as one question is

    convert 39cm to km and answer in scientific notation

    would that be 100000cm = 1km therefore 39/100000=0.00039

    is that right
    Yes, but it wants the answer in scientific notation, so in this case it would be

    3.9 ~10^{-4}

    RonL
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Grand Panjandrum
    Joined
    Nov 2005
    From
    someplace
    Posts
    14,972
    Thanks
    4
    Quote Originally Posted by aadkeski View Post
    and the one thats got me is

    a mass rests on an area of 80mm2 and exerts a force of 320 kg m/s2. express the pressure exerted on this area in kN/cm2

    i worked it out but not sure if im right

    so can you all help me out i will post more soon

    cheers dan
    What does 320 kg m/s^2 mean. The force that will accelerate 1 kg
    at 1 m/s^2 is 1 N, so on the face of it this is a force of 320 N.

    80 square mm = 80/10000 = 8/1000 = 0.008 cm^2

    Therefor the pressure is 320/0.008=40000 N/cm^2, or
    40 kN/cm^2.

    RonL
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Aug 2007
    Posts
    4
    THANKS

    when i see it all worked out its easier to understand. i have a heap more questions so should i post here.

    thanks again
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Grand Panjandrum
    Joined
    Nov 2005
    From
    someplace
    Posts
    14,972
    Thanks
    4
    Quote Originally Posted by aadkeski View Post
    THANKS

    when i see it all worked out its easier to understand. i have a heap more questions so should i post here.

    thanks again
    Yes, go ahead.

    RonL
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Help me with my grade 11 maths [easy maths]
    Posted in the Pre-Calculus Forum
    Replies: 11
    Last Post: December 27th 2009, 03:09 PM
  2. Replies: 3
    Last Post: November 15th 2008, 04:18 AM
  3. units Maths
    Posted in the Math Topics Forum
    Replies: 4
    Last Post: September 20th 2007, 01:40 PM
  4. Replies: 0
    Last Post: September 5th 2007, 02:50 AM
  5. Replies: 1
    Last Post: October 3rd 2006, 08:59 AM

Search Tags


/mathhelpforum @mathhelpforum