Heavier or lighter in a lift?

A person on a scale in a lift that runs a motion profile (start up, cruise, brake); the scale reads m(g + a) with a's sign set by acceleration, not by direction of motion.

Make the scale read less than mg while the lift is still moving upward (decelerating going up).

Moving up always means feeling heavier.

• Gravity acts at a distance; all other everyday mechanical forces are contact forces that arise where bodies touch.
• The normal reaction is the component of a contact force perpendicular to the surfaces in contact; it adjusts to whatever value prevents the bodies from passing into each other.
• Tension is the pull transmitted by a string. For a light (massless) inextensible string over a frictionless pulley, the tension is the same all along it.
• A spring exerts a restoring force F = −kx for small extension or compression x, where k is the spring constant; the negative sign shows it opposes the deformation.
• In a lift accelerating upward at a, a person's apparent weight (the normal force from the floor or the scale reading) is m(g + a); accelerating downward it is m(g − a).
• A lift moving up but slowing down has downward acceleration, so the scale reads less than mg. The direction of acceleration matters, not the direction of motion.
• In free fall (a = g downward) the scale reads zero; the body appears weightless though gravity still acts on it.

Teaching this idea? Put the simulation on your own page or LMS with this code.