Laws of Motion
Class 11 · Laws of Motion
Elevator: Apparent Weight
N = m(g+a) — feel heavier going up, lighter going down, weightless in free fall.
Key Notes
01
Apparent weight = N (normal force on a person).
02
Elevator accelerating up: N = m(g+a) → heavier feeling.
03
Accelerating down: N = m(g−a) → lighter feeling.
04
Free fall (a = g): N = 0 → weightlessness.
05
Constant velocity or at rest: N = mg (true weight).
Formulas
Apparent weight
a > 0 upward, a < 0 downward.
Important Points
Weightlessness in orbit is free fall — not absence of gravity.
Elevator: Apparent Weight notes from sciphylab (also known as SciPhy, SciPhy Lab, SciPhy Labs, Physics Lab). Class 11 physics revision for JEE Mains, JEE Advanced, NEET UG, AP Physics 1/2/C, SAT, and CUET-UG.