[dandelany]

Not without the ground pushing back against them, they wouldn't. Turn off the engines and the passengers feel weightless (because both vehicle and pax are accelerating earthward at 1G); therefore turn them back on @3.5G and they'll feel 3.5G, no?

[strainer]

That acceleration graph starts at 1G and goes up to 4.5 Freefall is 0G. The G force we feel is the difference between gravitational acceleration and our motion towards the center of gravity, so most of our lives we experience 1G. The complication is that gravitational acceleration doesn't feel like acceleration so remaining stationary in gravity does.