Displacement of a particle moving on the xy axis?

[JessicaJ283782]

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 vi= vii. As it passes through the region x = 0 to x = d, the electron experiences acceleration a = axi + ayj, where ax and ay are constants. For the case vi = 1.74 ✕ 10^7 m/s, ax = 7.84 ✕ 10^14 m/s2, and ay = 1.51 ✕ 10^15 m/s2, determine the following, at x = d = 0.0100 m.

(a) the position of the electron (yf=?)So, I went through, and I used the equation d=vi*t+.5(at^2)

I plugged in: .01=1.74*10^7t+.5(7.84*10^14)t^2

I got the time to be 5.67458*10^-10

Now, I know you have to plug the time into an equation, along with the acceleration of y, but I am confused on which equation to use since you only know acceleration and time for the y coordinates?(b) the velocity of the electron

So, I used: vf=vi+at

vf(x)=5.67458*10^-10 X 7.84*10^14

and wouldn't you do the same for the y coordinates?

Thank you!

 

[hjelmgart]

a)
So at this point in time, you now need to find the y-coordinate of the electron. You know the acceleration in the y-direction. Can't you find an equations, which you could then use? Perhaps the very same equation, you just used to find the time, just with different parameters?

 

[RTW69]

Actually you know the velocity of the electron in the y-direction it is 0 m/s, therefore v=1.74*10^7i+0j m/s
and a=7.84*10^14i+1.5*10^15j, you have solved for t and you know vi and ai so you can solve for y. You are almost there.