Free Fall: Measure g and Verify Conservation of Energy (Virtual Practical)
A virtual free-fall practical. Ticker tape: switch on before releasing, check the first gap, find v from neighbouring dots, and compare mgh with ½mv². Electromagnet and trapdoor (AQA RP3): repeat drops, plot h against t² or t against √h, and see how the release delay and measuring to the top of the ball affect g.
About this simulation
- What
- An interactive Physics simulation of Free Fall: Measure g and Verify Conservation of Energy (Virtual Practical).
- Who
- Designed for AP, IB, and A‑Level Physics students.
- How
- Runs in any modern browser — drag, adjust, and explore in real time.
Updated 2026-10-11
Key Concepts
Free fall
Without air resistance every object falls with the same acceleration g: h = ½gt² and v² = 2gh from rest.
Speed from a tape
The speed at a dot is the average speed over the two neighbouring gaps: vₙ = (hₙ₊₁ − hₙ₋₁) / 2T. Using v = gt or v = √(2gh) assumes what you are testing.
ΔEk a little below ΔEp
Friction at the timer and air resistance take a little energy, so ½v² comes out slightly less than gh. Clearly more than gh means a method error.
Graphs remove constant errors
A delay in the electromagnet adds a constant time; t against √h puts it in the intercept. Measuring h to the top of the ball adds a constant height; h against t² puts that in the intercept.
What This Free-Fall Lab Teaches
Two classic free-fall practicals in one lab. Verifying conservation of mechanical energy with a ticker timer is a standard experiment in the Chinese textbook (验证机械能守恒定律); measuring g with an electromagnet and trapdoor timer is AQA A-level required practical 3.
With the ticker tape you choose the timer and the falling object, decide the order of switching on and releasing, and analyse the tape: the first gap, the speed at each dot and the comparison of ½v² with gh. With the trapdoor you set the electromagnet current, decide where to measure the height to, repeat drops and choose the graph.
The model includes the things that make real results differ from the ideal: friction at the timer, air resistance, the electromagnet's release delay and constant errors in height. The analysis shows how each one shows up — in ΔEk/ΔEp, the gradient or the intercept.
Frequently Asked Questions
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