An archer stands 40.0m from the target. if the arrow is shot horizontally with a velocity of 90.0 m/s, how far above the bull's eye must she aim to compensate for gravity pulling her arrow downward?

Ok, first we need to have in mind that to findthe distance we need to find also the time then we use the kinematic equations in the x-direction 

delta x = Vox*t + 1/2*a*t^2 
since there is no horizontal acceleration, a = 0 m/s/s 
delta x = Vox*t 
40.0 m = 90 m/s * t 
t = 4/9 s 

Now using this time you can calculate the vertical displacement due to gravity. 
delta y = Voy*t + 1/2*g*t^2 
since there is no initial vertical velocity, Voy = 0m/s 
delta y = 1/2*g*t^2 
delta y = 1/2*(-9.81 m/s/s)*(4/9 s)^2 
solve for delta y and you will have the answer

3x + 2x = both people using the same measure of like 5x = x= 25 meters per second. 25ms. it takes them 4 seconds to

It won't lose or gain electrons if it's a covalent bond it shares the electrons with another atom or atoms. if it is an ionic bond it will lose the 3 electrons on the outer shell and become a positively charged ion.  credit goes to @sunshinebaby of answers.yahoo.com.