In this video clip gas from the fire extinguisher goes backwards propelling the man on the skooter forwards.

In this video clip the man stands on a set of scales.  as he accelerates upwards he experiences a greater force due to gravity.  in the middle of the ride he experiences normal gravity.  as the elevator stops he feels lighter than normal. The units used are wrong but substitute Newtons for Pounds then the explanation holds true. as you accelerate away from the Earth, you experience a greater than normal gravitational force pulling you down and it feels as if your stomach has sunk to your toes. the middle of the ride you are traveling at a constant speed so normal gravitational forces are felt. as you slow down at the top, you experience less than normal gravitational forces and it eels as if your stomach has moved up into your throat.