Motion LabFORCES · MOTION · MOMENTUM

A trolley & two light gates

Predict the time between the gates. Then measure it.

BUILD

Object Change Initial conditions · edit in Build

In Build, click or drag apparatus. Tab selects the next object, arrow keys move it, Enter opens Controls. Use the properties form for exact measurements. Space runs or pauses. Escape cancels placement or dragging. Enter places a new part at the centre. Drag the circular velocity handle to set initial velocity, or use the quick controls.

YOUR LINEAR MOTION EXPERIMENTTrolley A selected

0.000s

Drag the trolley or a gate. Make a prediction. Press Run.

100%

MODEL VALUESTrolley AAlong the track · positive to the right

Velocity1.50 m/s

Acceleration0.00 m/s²

Momentum1.50 kg m/s

Kinetic energy1.13 J

Plot Live data · select an object to follow it

Run your experiment to collect data. Click the graph to inspect a recorded moment.

0.000 s

LIGHT GATES · measured speedRun to measure a flag crossing.

TRY A CHALLENGEStop in the target zone.

Choose an investigation

Prepared experiment

Each workspace retains its build while this tab is open. Keep a run before changing an initial condition to compare results.

Experiment title

JSON saves the initial setup. Kept runs and measurements remain in this tab; use CSV to download them.

Customise your experiment

Build mode · change initial conditions, then Run.

Lock construction for teaching

ADD A PART MEASURE

Click a part,
then place it.

SELECTED APPARATUS

Model settings

Velocity Forces Momentum Motion trail Grid

Advanced

Experiment notebook

A timing flag interrupts each beam. Gate speed = flag length ÷ interruption time.

Event

Run a collision experiment to compare momentum and kinetic energy.

Recorded model values. SI units; acceleration and contact force are averages over a simulation step.

A LITTLE HELP GETTING STARTED

Make a prediction.
Put it to the test.

Build your experiment. Choose a starting experiment or place apparatus from the tray. Drag it into position, then use Controls for exact values.
Choose the physics. Set mass, velocity, force, friction and collision behaviour. A positive track slope runs downhill to the right.
Run and measure. Pause, slow down or step by 1/30 second. Light gates time a flag on the 1D track. In the other spaces they record centre crossings and show a model velocity component normal to the beam.
Look closer. The graph stays beside the experiment. Open Notebook for Light gates, Collisions or Results. Scrub the timeline to replay. Keep a run before changing one variable.

Keyboard: Tab through apparatus on the canvas, arrows move a selected part (Shift for smaller steps), Enter opens Controls, Delete removes a part. Space runs/pauses. Ctrl+Z and Ctrl+Y undo/redo in Build. Enter places a chosen part at the view centre. Drag the velocity arrow tip to set the initial velocity. Wheel zooms about the pointer; Pan or right/middle drag moves the view. Teacher view enlarges readings; Lock construction prevents edits. The Controls panel holds overlays, gravity, friction, colour and precise geometry.

Model: SI units, fixed simulation steps, ideal trolleys without wheel inertia. Free circular bodies use uniform-disc inertia. Top-down weight and support act out of the screen. Rough patches use the puck centre to select the material. Rigid collision forces are step averages, not physical peak forces. Recording stops at 120 simulated seconds.

Keep your work: Save experiment downloads the arrangement. Export CSV downloads measurements. The latest build is recovered locally when storage is available. Kept runs stay in this tab.