1) Pick a force. 2) Press on the diagram and drag outward in the direction it points. Longer arrow = bigger force. Drag an arrow’s tip to fix it.
What will it do next?
Live graphs
Data table
Record every s
How to use this simulator (students & teacher notes)
Pick a scenario at the top, or a “Try:” preset. Every number can be changed in Settings.
▶ Run animates the motion using Newton’s 2nd law, Fnet = ma. Force arrows on the object are drawn to scale (longer = bigger force) from the object’s center. The dashed gray arrow is the net force, which is the sum of the forces, not another force.
The free-body diagram panel shows only the object as a dot, with every force acting on it.
Predict mode: the arrows and numbers are hidden. Build your own free-body diagram for the moment shown (you can pause a run partway and predict at that moment). Pick what the object will do, then press Check. The sim tells you about missing forces, extra forces that don’t exist (like a “force of motion”), wrong directions, and arrows that are the wrong size compared to each other. Reveal shows the correct diagram over yours (yours dashed) and runs the motion.
Level: “Regents” hides angled pushes, components, tilted axes, two-rope and pulley problems. “AP Physics 1” shows all of them plus the static friction threshold μsFN.
Graphs show velocity, acceleration, and net force vs. time along the direction of motion (signs: see the + direction under each scenario). The data table records t, position, v, a, Fnet and every force while it runs. Download CSV opens in Google Sheets or Excel.
Physics used: Fg = mg (g = 9.8 m/s² by default). Static friction matches whatever is needed up to μsFN. Once the object slides, kinetic friction is μkFN opposite the sliding. Air resistance is Fair = kv². In the elevator the scale reads FN = m(g + a).