1) an electron is accelerated to 200m/s in a distance of 3G. What was the acceleration of the electron? 2) a rock is thrown 30m high. How long does it take to be caught at the same level? Please help my teacher said there's a quiz tomorrow but she hasn't taught much

1. Um... what does '3G' mean? I never saw that before...

Anyway, use the kinematics formula:

v^2 = u^2 + 2as

v = final velocity
u = initial velocity
a = acceleration
s = distance

2. Another equation that might help you is:

s = ut + \frac12 at^2

And taking into account that the time to go up is the same time to go down, you take the time for the stone to fall down from 30 m, that is the initial velocity = 0, s = 30, a = g

Hey thanks I meant 3m but I understood that formula! Thanks again!

Lol, okay, cheers! :)