1. The problem statement, all variables and given/known data Jean, who likes physics experiments, dangles her watch from a thin piece of string while the jetliner she is in takes off from Dulles Airport. She notices that the string makes an angle of 21° with respect to the vertical while the aircraft accelerates for takeoff, which takes about 16 seconds. Estimate the takeoff speed of the aircraft. 2. Relevant equations Fnet=ma 3. The attempt at a solution In my class we've just been these problems with 2 variables and I'm confused about finding the first part of the problem so that I can do the later half. I know that since I have time I'm trying to find acceleration or velocity but I don't know where to begin.