Experimental design and analysis (LAB)
Launch speed from range and height
- Unit 1
- 10 points
- About 27 minutes
You can use a calculator on this question, just like on exam day.
A two-part lab question. First you design an experiment to answer a question: what you change, what you measure, the equipment and how you would analyze the data. Then you get a data table from a similar experiment, choose what to graph (often so the points fall on a straight line), plot it and use the slope, the intercept or the graph's shape to answer a question. On the exam: Question 3 of 4. New for May 2027: the free-response section is 95 minutes, down from 100, for all 4 questions (50% of your score), one of each type in this order. Calculator and equation sheet allowed. The CED suggests 25–30 minutes. This question type started in May 2025, so Physics C: Mechanics free-response questions from 2024 and earlier are built differently.
The question and its sources
Students want to determine the launch speed of a small ball fired by a spring launcher. The launcher fires the ball horizontally with the same speed every time. The students have no device that measures time or speed directly.
Part A: Available equipment
A spring launcher that fires a small steel ball horizontally, a ring stand and clamp that can hold the launcher at any height above the floor, a meterstick, a long tape measure, a plumb bob, white paper, carbon paper, tape, and a protractor.
Source: Hypothetical lab setup
Part B: Table 1. Horizontal range for different launch heights (each range is the average of five launches)
| Launch height h (m) | Horizontal range D (m) |
|---|---|
| 0.20 | 0.64 |
| 0.40 | 0.93 |
| 0.60 | 1.11 |
| 0.80 | 1.30 |
| 1.00 | 1.43 |
| 1.20 | 1.59 |
Source: Hypothetical data
Suggested time: 27 minutes
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Part (A(i))
3 pointsUsing only the equipment listed in the setup, describe an experimental procedure you could use to collect data that would allow you to determine from a graph. Include what you would measure and how, what you would vary, and one step you would take to reduce experimental uncertainty.
Type math plainly, like x^2, sqrt(x) or (x+1)/(x−1).
0 / 2,500 characters
Part (A(ii))
2 pointsDescribe how you would use your data to determine . Include what you would graph and how you would use the graph.
Type math plainly, like x^2, sqrt(x) or (x+1)/(x−1).
0 / 2,500 characters
Part (B(i))
1 pointAnother group collected the data in Table 1. Indicate which quantities you would graph to produce a straight line that could be used to determine . Calculate the values you would plot.
Type math plainly, like x^2, sqrt(x) or (x+1)/(x−1).
0 / 2,500 characters
Part (B(ii))
2 pointsPlot the quantities you chose and draw a best-fit line. You can't draw here, so describe the graph you would draw: what goes on each axis (with units), the scale, the points you would plot, and the best-fit line.
Type math plainly, like x^2, sqrt(x) or (x+1)/(x−1).
0 / 2,500 characters
Part (B(iii))
2 pointsUsing your best-fit line, calculate an experimental value for .
Type math plainly, like x^2, sqrt(x) or (x+1)/(x−1).
0 / 2,500 characters
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