Help I got answer A correct but cannot get B. In the figure, a uniform, upward-p

Question

Help I got answer A correct but cannot get B.

In the figure, a uniform, upward-pointing electric field E of magnitude 1.50×103 N/C has been set up between two horizontal plates by charging the lower plate positively and the upper plate negatively. The plates have length L = 4 cm and separation d = 2.00 cm. Electrons are shot between the plates from the left edge of the lower plate.
The first electron has the initial velocity v0, which makes an angle =45° with the lower plate and has a magnitude of 5.13×106 m/s. Will this electron strike one of the plates? If so, what is the horizontal distance from the left edge? If not enter the vertical position at which the particle leaves the space between the plates.
2.76×10-2 m

Another electron has an initial velocity which has the angle =45° with the lower plate and has a magnitude of 3.31×106 m/s. Will this electron strike one of the plates? If so, what is the horizontal distance from the left edge? If not enter the vertical position at which the particle leaves the space between the plates.

Explanation / Answer

to determine whether the electron strikes one of the plates oenot we need to calculate

If Ty < Tx, then the electron will strike the negative plate.

If Ty > Tx, the electron will not strike the plate and we will then determine the vertical

distance at which the particle leaves the space between the plates.

tne time required to travel a vertical distance of y = 0.02m

and time Tx for a horizontal distance of x = 0.04 m

use the kinematic equations Vy = Vx = Vo sin 45

Vy = Vx = 3.31 e6 * sin 45 = 2.34 e6 m/s

use for time along vertical Kinematic eqn S = Y + ut + 0.5 at^2

along x axis, S = UTx

here use ma = Eq

a = Eq/m

a = 1.5 e 3* 1.6 e-19/(9.11 e-31)

a = 2.63 e 14 m/s^2

so for vertical : 0.02 = 0 + (2.34 e 6 * Ty) + (0.5 * 2.63 e 14 * Ty^2)

1.315e14 Ty^2 + 2.34 e 6Ty -0.02 = 0

using Quadratic form, Ty = (-2.34e6) +- sqrt(5.475e12)+ (4*1.315 e14 *0.02)/2a

Ty = 2.37 e -9 secs

similar;y for Tx,

use Tx = S/u = 0.04/2.34 e6

Tx = 1.709 e -8 secs

as Ty < Tx,

The electron will in fact strike the plate at a horizontal distance of

x = 0+(2.34e6*1.709 e-9)

x = 0.0399 m.

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