Resultant force
•••
What this model shows
The puck floats on air with no friction at all, and the rubber bumper stops it where it meets the rim. Each force meter is moved along with the puck so that its pull stays exactly the same in size and direction; in a real lab the pull wavers a little.
The positions come from F = ma worked out exactly, not from measurements. On the circle the string’s pull is the force needed for a steady circle; the pin lets the string go exactly at the mark.
Runs are replayed at half speed so that they are easier to follow; the times on the graph are the real times. Real readings are taken in a lab; this is simulated apparatus.
With reduced motion each run is drawn complete at once, and the puck goes straight to where it stops.
Select equipment to read its description in the card.