gals to meters per second squared

Why you don't feel speed — only its change

You're racing along at nearly a thousand kilometers per hour, ten kilometers up, and calmly pouring a coffee. A one-second climb to the top of a roller coaster pins you to your seat. Why? Because the body has no sense of speed — it reacts only to acceleration. Here is the physics of that difference, from an 1901 decree to Colonel Stapp's 46 g.