Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Basic linear motion question.Is it good?

  1. Aug 20, 2010 #1
    1. The problem statement, all variables and given/known data
    Airport runway designing:

    (i)lowest acceleration rate of any plane is likely to be 3m/s^2.Take off speed for this airplane will be 65m/s.what is minimum allowed length of runway?

    (ii)If airplane accelerates down runway at 3.2m/s^ for 32.8 seconds until it lifts off..determine distance travelled before take-off.

    (iii)Another airplane has take off speed of 88.3m/s and needs 1365m to reach this speed.determine acceleration of plane and time taken to reach this speed.

    2. Relevant equations
    v=u+at

    v^2=u^2+2as

    s=ut+(1/2)at^2


    3. The attempt at a solution


    (i) a=3
    u=0
    v=65
    s=? v^2=u^2+2as

    65^2=0^2+2(3)s
    4225=6s
    s=4225/3
    s= 704.2 m

    (ii) a=3.2
    t=32.8
    u=0
    s=?
    s=ut+(1/2)at^2

    s=0(32.8)+(1/2)(3.2)(32.8)^2

    s=1721.3m

    (iii)v=88.3
    u=0
    s=1365
    t=?

    v^2=u^2+2as

    (88.3)^2=0^2+2a(1365)

    7796.89=2730a

    a=2.856m/s^2

    Now:
    v=u+at

    88.3=0+2.856(t)

    t=30.9 seconds

    Thanks in advance
     
  2. jcsd
  3. Aug 20, 2010 #2

    collinsmark

    User Avatar
    Homework Helper
    Gold Member

    'Looks okay to me. :approve:
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook