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Homework Help: 2D Motion Question

  1. Dec 6, 2004 #1
    Find the dx for an object projected at 100 m/s from 20 degrees to 70 degrees in 5 degree intervals. How would you exactly do this? Would you use the equation Ay = A sin X?
     
  2. jcsd
  3. Dec 6, 2004 #2
    break up your Vi=100m/s at 20 degrees into the x&y components

    Vix=Vi*cos(20 degrees)
    Viy=Vi*sin(20 degrees)

    assuming you are on earth and ingoring air friction
    use
    Vf=Vi+(-9.8m/s^2)*t
    to get
    t=(Vf-Vi)/(-9.8m/s^2)

    lettin Vf=0 to find time to max height
    double it to get the total air time

    use total time in
    dx=Vix*t
     
  4. Dec 6, 2004 #3
    Do I have to do Viy=Vi*sin(X) repeatedly until the equation is Viy=Vi*sin(70)? Do you have a screen name so we can talk one-on-one?





     
  5. Dec 6, 2004 #4
    you could use theta in terms of n like this

    theta=20+5n
    where n is a whole number between 0 and 10

    use your basic algebra to substitute in variables, ie: the for t in dx=Vix*t put dx=Vix*-2Viy/(-9.8m/s^2)

    do the same for Vix and Viy, and then again for theta.

    SN: PBGartist (aim)
    58362144 (icq)
    pbgartist@hotmail.com (msn)
    Real_Skotster (yim)
     
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