Hiya, Ok I have several concepts I've tried to undestand but still can't seem to get how it works... 1) In sports, you see people "hang" in the air? What exactly is the mechanism behind this...All I can understand is that say a basketball player is jumping and his legs are bent vs straight. He can "stay" longer in the air because his center of mass stays at the same level?? or something like that? 2) Also, during an airplane takeoff, you have a odd feeling due to the acceleration but when you're in the sky, eg. once the plane levels off, you don't feel anything...why the heck is that? 3)Why is it that you get on an elevator and then when it goes up, you feel heavier? my book said something about the reaction force of the ground being less...etc, I want to know a bit more. If anyone can just answer one of these, that would be much appreciated! :rofl: Remember, dumb it down, I mean really dumb it, I'm not very physics apt lol. Thanks all.