2 charged plates with a charged particle?

Question

A particle with mass of 2.50x10^-6 kg and with positive charge of 3.50x10^-6 C is motionless at the bottom of a pair of parallel plates, (they are 1.5 m apart positive charged on bottom, negative charged plate on top) when a voltage of 12.0 V is applied. Ignore gravity and assume a vaccum, how long does it take for the particle to reach the top?

thank you kindly

Answer 1

Force on charge= Eq

but E = dV/dr= 12/1.5

so: F= (12/1.5)*3.5*10^-6  = 0.000028 N

now: s=0.5*a*t^2=1.5meter

from F=ma, a=F/m

a=(0.000028)/(2.5*10^-6) = 11.2 m/s^2

t=sqr(s/(0.5*a)= sqr(1.5/(0.5*11.2))

t = sqr(1.5/(0.5*11.2)) = 0.517 seconds