They should draw a vague rocket shape pointed upwards. It will have one arrow pointing straight down through the rocket marked "gravity", "g", or "g=9.81kg m/s^2" etc. Another arrow should also be pointing down and say "drag" or "air resistance" etc.It should NOT have an arrow pointing upwards that says "launch force", "thrust", "lift" etc as all the force was delivered to the rocket originally when air was forced in through the bike pump.