if i were you i would ask look through the task notification and see what the dot points are and go from there - esp if you do the experiment and then have to do a mini exam on the topics covered or need to present bc the syllabus dot points give away what is most important and probably most likely to be assessed later on.
also whenever i had an investigative task i always asked the teacher what people have done in the past and chances are the ones that teachers remember are from the ppl that did the best.
for mod 1 and 2 its literally so broad loll. just about any object in 2d motion will work so like a ferris wheel, a DIY parachute dropping etc. in the past i did an amusement ride, question was something like: how does the ideal/theoretical model of the motion of this amusement ride compare to the real-life model. i used tracking software and a video to analyse the motion and like compared the two.