Weight & Normal Force

Free-body diagrams and elevators

An interactive lesson with 7 steps, about 6 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Weight W = mg is a force (in newtons). Mass (in kg) is the same everywhere.
• A free-body diagram shows every force on one object.
• The normal force adjusts itself: $N = m(g + a)$ when accelerating upward. In free fall, $N = 0$.

Steps

1. Mass vs. weight
2. Mass and weight are different
3. Free-body diagrams
4. Elevator going up
5. How much heavier?
6. Going down
7. Snap!