At sea level, a hydrogen molecule in the air has an average kinetic energy of 5.53×10-21 J. Its mass is 3.32×10-27 kg. The hydrogen molecule shoots straight up without colliding with the molecules in the air. (Assume that you can use g = 9.81 m/s2; although we’ll see in Chapter 12 that this assumption may not be justified for this situation.)

I found the initial speed to be: 1825.2 m/s

but now i need to find How high would it rise?
in order to do that i would use the equation: vf^2=vo^2+2a(x-xo)

I have everything to plug in to find the height EXCEPT for the final velocity, what is the final velocity? or how would i find it?

Thank You so much :)

final velocity at max height is zero.