Results 1 to 8 of 8

Thread: Question

  1. #1
    pacey0006
    Guest

    Question

    Could someone help me answer this question?

    A bicycle and rider moving at 26 km/h have a kinetic energy of 1.5 kJ.
    What is the approximate combined mass of the bicycle and rider?

    I cant figure it out. I was using the KE = 1/2mv^2 formula
    which rearranges to mass = 2KE/V^2 ?

    The answers apparently 57.5kg.

  2. #2
    New Member
    Join Date
    Nov 2011
    HSC
    N/A
    Gender
    Male
    Posts
    23
    Rep Power
    3

    Re: Question

    fuck engineering studies. just fuck it. seriously just fuck it up theass wif a giant epdilso.

  3. #3
    pacey0006
    Guest

    Re: Question

    true ?

  4. #4
    Cadet zhou's Avatar
    Join Date
    Nov 2011
    HSC
    2012
    Uni Grad
    2017
    Gender
    Male
    Location
    Sydney
    Posts
    35
    Rep Power
    3

    Re: Question

    Quote Originally Posted by pacey0006 View Post
    Could someone help me answer this question?

    A bicycle and rider moving at 26 km/h have a kinetic energy of 1.5 kJ.
    What is the approximate combined mass of the bicycle and rider?

    I cant figure it out. I was using the KE = 1/2mv^2 formula
    which rearranges to mass = 2KE/V^2 ?


    The answers apparently 57.5kg.
    you were right, make sure you converted kJ into J and converted km/h into m/s, sub them in and you'll get 57.5
    ok

  5. #5
    Cadet
    Join Date
    Mar 2009
    HSC
    2012
    Gender
    Male
    Posts
    35
    Rep Power
    5

    Re: Question

    Quote Originally Posted by pacey0006 View Post
    Could someone help me answer this question?

    A bicycle and rider moving at 26 km/h have a kinetic energy of 1.5 kJ.
    What is the approximate combined mass of the bicycle and rider?

    I cant figure it out. I was using the KE = 1/2mv^2 formula
    which rearranges to mass = 2KE/V^2 ?

    The answers apparently 57.5kg.
    1.5x10^3 = 1/2 x m x (26/3.6)^2
    Therefore m = 1.5x10^3 / 26
    m = 57.5kg

  6. #6
    Cadet
    Join Date
    Sep 2011
    HSC
    2012
    Gender
    Male
    Posts
    81
    Rep Power
    3

    Re: Question

    Quote Originally Posted by Washy_182 View Post
    1.5x10^3 = 1/2 x m x (26/3.6)^2
    Therefore m = 1.5x10^3 / 26
    m = 57.5kg
    You forgot a few bits
    1.5x10^3 = 1/2 x m x (26/3.6)^2
    m=(2x1.5x10^3 )/(26/3.6)^2
    m=57.5Kg
    3unit maths, Physics, Chemistry, Standard English, Wood technology,Engineering through Distance Ed

    2012 ATAR: 93.9
    Comprehensive Industrial Technology (Timber) Portfolio for Sale, Received (19/20, 20/20, 20/20 in school marks, 96 HSC Mark) 77 pages long, best used as a skeleton to design your own portfolio. Covers all the outcomes with immense detail and related research. Price negotiable Contact at Ben.Brown94@hotmail.com

  7. #7
    Cadet
    Join Date
    Mar 2012
    HSC
    N/A
    Gender
    Male
    Posts
    65
    Rep Power
    2

    Re: Question

    Someone got caught out by the good ol' SI unit trick!

    Look out tomorrow, its certain to be there once, twice or even three times!

  8. #8
    Cadet
    Join Date
    Mar 2009
    HSC
    2012
    Gender
    Male
    Posts
    35
    Rep Power
    5

    Re: Question

    Quote Originally Posted by BenBrownTown View Post
    You forgot a few bits
    1.5x10^3 = 1/2 x m x (26/3.6)^2
    m=(2x1.5x10^3 )/(26/3.6)^2
    m=57.5Kg
    Still got the right answer though...

    Markers will look at my working and give me full marks, even though I was lazy and skipped a line of working.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

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