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Homework Help: Motion in 2 dimensions!

  1. Oct 16, 2008 #1
    1. The problem statement, all variables and given/known data
    As an example of the manipulation of an electron beam, consider an electron traveling away from the origin along the x axis in the xy plane with initial velocity v = vi. As it passes through the region x = 0 to x = d, the electron experiences acceleration a = ax + ay, where ax and ay are constants. For the case vi = 1.95 107 m/s, ax = 8.04 1014 m/s2, and ay = 1.52 1015 m/s2, determine the following, at x = d = 0.0100 m.

    2. Relevant equations
    (a) the position of the electron
    yf = m
    (b) the velocity of the electron
    vf = m/s + m/s
    (c) the speed of the electron
    |vf| = m/s
    (d) the direction of travel of the electron (i.e. the angle between its velocity and the x axis)
    = °
    3. The attempt at a solution
    for this problem i used the kinematic equation and manipulated them and didnt get the right answers..i am a bio major, not a physics major, why do i have to learn this!! please somebody help!
  2. jcsd
  3. Oct 17, 2008 #2
    Please show us HOW you used the kinematics equations... then we can better help you.
  4. Oct 17, 2008 #3
    well, for a) i found t by using t=d/v and got 5.13E-10 s. i found theta by arctan Ay/Ax and i got 27.9 degrees. so then i used yf=yi+(V_yi)t-.5(9.80)t^2 to find the yf and i got 4.67E-3 and it was wrong.

    for b)i found the velocity unit vectors and i got it wrong. i did Vxi= Vi(cos27.9) and Vyi= vi(sin27.9).... so i couldnt go on to c and d
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