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

> G-force calculator: elevator scale readings incl. free fall, coaster loop and airtime g, space-station artificial gravity, human tolerance chart and g from Δv.

- URL: https://qilingtools.com/en/physics/g-force
- Category: Physics Tools (https://qilingtools.com/en/physics)
- Tags: [Physics](https://qilingtools.com/en/tags/physics), [Education](https://qilingtools.com/en/tags/education)
- Last updated: 2026-10-29
- Price: Free, no sign-up
- Privacy: Runs locally in the browser; files are never uploaded

On the elevator tab, choose going up, going down or a snapped cable and watch the bathroom-scale reading follow the velocity profile, dropping to zero in free fall. The roller-coaster tab uses the loop entry speed and radius to give the felt g at the bottom, the top and every point in between, tells you whether the car would leave the track, and works out airtime over hills. The space-station tab turns radius and spin rate into artificial gravity, head-to-foot gradient and Coriolis effects with a comfort rating. The tolerance tab plots approximate human limits for different directions alongside sneezes, F1 braking, fighter turns, rocket launches and car crashes on one log chart, and converts a change in speed over a time or distance into an average g.

## How to use

1. On the Elevator tab, choose a scenario, set mass, acceleration and top speed or the free-fall time, and press Play
2. On 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. On 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. On the Tolerance tab, compare the events, then enter a speed change with a time or stopping distance to compute the average g

## Features

- Elevator up, down and cable-snap profiles with an animated scale reading and charts
- Point-by-point loop g-load n = v²/(gR) + cosθ, track-leaving check and minimum entry speed
- Hill airtime and valley g-loads
- Artificial gravity, rim speed, head-to-foot gradient, Coriolis ratio and a spin-rate comfort chart
- Approximate +Gz, −Gz and +Gx tolerance curves with 16 familiar events
- Average g from Δv and time or distance, marked on the tolerance chart

## 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.

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