The use of accelerometers to measure the motion produced by inertial force, centrifugal force, centripetal force, and gravitational force is at the basic foundation of all experimental physics. The paradox here is that these simple measurements are more or less misunderstood by both scientists and laypersons alike. It seems that almost no one is capable of fully understanding the nature of these forces and motions or accepting their measurements at face value. Everyone, including Einstein, seems to have gotten it either backwards, inside out, or upside down.