Simple "what is velocity at time t" problem 1. The problem statement, all variables and given/known data A helicopter is lifting off. The only forces are air (up) and gravity. What is the vertical speed at time t if it took off at time t=0? 2. Relevant equations g = F(air)/m, g=Δv/Δt 3. The attempt at a solution F(air)/m = Δv/Δt v = tF(air)/m, but I'm told that this is wrong. I believe I need to include g. What am I missing?