Weight & Weightlessness
Elevator scale simulator. Builds on Newton's Three Laws.
You're standing on a bathroom scale inside an elevator. The elevator suddenly accelerates UPWARD.
What happens to the scale reading?
The scale reads MORE! A scale measures the normal force, not gravity. When accelerating upward, the floor must push harder: N = m(g + a). If you weigh 70 kg, accelerating at 2 m/s² makes the scale read ~84 kg. Accelerating downward? The scale reads LESS. Free fall (a = g)? The scale reads ZERO — weightlessness!
Loading simulation…
Ride the elevator through different phases — watch the scale reading and force arrows change in real time.
N = m(g + a)
When a = −g (free fall), N = 0. You're weightless — not because gravity disappeared, but because nothing is pushing back against it.
At the top of a loop, you feel lighter (centripetal acceleration subtracts from g). Go fast enough, and you feel pressed INTO the seat — heavier than normal.
NASA's training plane flies parabolic arcs. At the top, everything inside is in free fall for ~25 seconds — true weightlessness without leaving Earth's gravity.
Your bathroom scale never actually measures your weight (mg). It measures the floor's push on you. On Earth, they're equal — but not in an elevator or on another planet.
“Weightlessness doesn't mean no gravity. It means no support force. Astronauts float not because gravity vanished, but because the floor stopped pushing.”
Elevator Ride Designer
Design your own elevator journey — set the acceleration at each phase and watch how the scale reading changes throughout the ride.
Loading simulation…
Create a free-fall phase (a = −9.8 m/s²) and watch the scale hit zero. Then try accelerating upward at 2g — the scale reads THREE times your weight!
The maximum acceleration a human can survive is about 9g (~88 m/s²). Fighter pilots experience up to 9g in tight turns. At that point, blood can't reach your brain.