🎢G-Force Calculator - Elevator Weight, Roller Coaster Loops, Artificial Gravity

How to use G-Force & Apparent Weight Calculator

1. 1On the Elevator tab, choose a scenario, set mass, acceleration and top speed or the free-fall time, and press Play
2. 2On the Roller coaster tab, set the loop entry speed and radius, watch the animation and g curve, then adjust crest and valley speeds and radii
3. 3On the Space station tab, pick a preset or enter radius and rpm, or set 1 g in one click, and check the comfort rating
4. 4On the Tolerance tab, compare the events, then enter a speed change with a time or stopping distance to compute the average g

FAQ

Why do I feel heavier when an elevator starts going up?

A scale reads the force it pushes on you with. When the elevator accelerates upward, the floor must hold up your weight and also supply ma to accelerate you, so the reading becomes m(g + a). Slowing on the way up or speeding up on the way down gives m(g − a) and you feel lighter. Ordinary elevators accelerate at about 1 m/s², changing the reading by about 10%. In free fall a = −g and the scale reads zero, which is weightlessness; real elevators have overspeed governors and safety brakes that clamp the car to its rails.

Why don’t riders fall out at the top of a loop?

At the top the rider needs a centripetal acceleration v²/R. If that exceeds g, gravity alone is not enough and the seat must push down as well, so the felt load n = v²/(gR) − 1 is positive and you are pressed into the seat. To keep n ≥ 0 at the top of a circular loop the entry speed must be at least √(5gR), which means 6 g at the bottom. Modern coasters use teardrop (clothoid) loops: a tight radius at the top gives enough centripetal acceleration at lower speed, and a wide radius at the bottom keeps the g-load reasonable.

How fast must a space station spin for 1 g?

Artificial gravity is the centripetal acceleration a = ω²r. A 100 m radius needs about 3 rpm; a 1 km radius only about 0.95 rpm. Studies suggest most people feel fine below 2 rpm, need gradual adaptation between 2 and 6 rpm, and suffer strong vertigo from Coriolis effects when turning their heads at faster rates. A small radius also makes gravity at the head noticeably weaker than at the feet, which is why proposed large stations have radii of hundreds of metres or more.

How many g can a person withstand?

It depends on direction and duration. +Gz (eyeballs down, pressed into a seat) drains blood toward the legs; without a g-suit, 4–6 g for a few seconds can cause greyout or loss of consciousness, while fighter pilots with g-suits and straining manoeuvres hold 9 g for 10–20 seconds. −Gz pushes blood to the head and is tolerated only to about −2 to −3 g. Chest-to-back Gx is tolerated best, which is why astronauts launch and land lying on their backs, and John Stapp survived a 46 g peak on a rocket sled. The shorter the pulse, the higher the peak the body can take.

How can I estimate the g-force in a car crash?

Use constant deceleration: with a speed change Δv and stopping distance d, the average acceleration is a = Δv²/(2d), the time is t = 2d/Δv, and dividing by 9.81 gives g. In a 50 km/h crash into a wall, the crumple zone plus seat-belt stretch give the occupant about 0.5–0.7 m to stop, an average of roughly 15–20 g with higher peaks. Unbelted, hitting the wheel or windscreen over a few centimetres, the g-load is about ten times larger. Crumple zones, seat belts and airbags all work by stretching the stopping distance.