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Here is the problem

You are standing on top of a building, 30 m above the ground. You throw a ball (m = 0.15 kg) with an initial velocity or 20 m/s (in the y direction). Air resistance is given as (1/30)*v (yet again only considering the y direction because range is not an issue here).

a) find the maximum height of the ball

b) find the time t when the ball hits the ground 30 m below you

Ok so I set it up like this

mv' = -mg - v(1/30)

v' = -g - v(1/30m)

from here I get kind of confused.

I tried this

v' + v(1/30m) = -g

(e^(t/30m)v)' = -ge^(t/30m)

integrating:

e^(t/30m)v = -30mge^(t/30m) + c

v = -30mg + c/(e^(t/30m))

I'm pretty sure I'm wrong by here. Help would be appreciated.