Yes, I am running out of time! Well, we've studied all the major mechanics subjects. Kinematics, tension, friction, pulley systems, rigid body, oscillation, momentum, torque, and energy. {Not in the correct order, just listing off the top of my head} So far, I don't know to be honest. Everything i keep thinking of doesn't really relate to physics. I had a thought for using a keyring and attaching to the inside of a backpack or purse, a magnet would be on one end and you could use another sticker type magnet to apply to anything you use often for example, chapstick. It gets lost all the time in your bag and it would be nice if you always had it there. The keyring would just be so that you could pull on your chapstick and know its attached to it all the time. But again, i don't know if that has anything to with physics haha. I think one other student said he was going to make a cushion device for his phone so that if he ever drops it, the phone is cushioned and reduces the damage the phone goes through.
I can't think of anything that would be a pretty good physics related invention and not too complex to build either!