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Figure 5 shows a strip of steel of rectangular cross-section clamped at one end - AQA - A-Level Physics - Question 2 - 2022 - Paper 3
Question 2
Figure 5 shows a strip of steel of rectangular cross-section clamped at one end. The strip extends horizontally over the edge of a bench. A mass m is suspended from... show full transcript
Worked Solution & Example Answer:Figure 5 shows a strip of steel of rectangular cross-section clamped at one end - AQA - A-Level Physics - Question 2 - 2022 - Paper 3
Step 1
Explain a procedure to avoid parallax error when judging the reading indicated by the position of the pin on the ruler.
Answer
To avoid parallax error when judging the reading on the ruler, the student should:
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Place a Mirror Behind the Ruler: Position a small mirror behind the ruler so that the reflection of the pin can be seen. This allows the student to align their line of sight properly.
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Adjust Position: The student should then adjust their position or the height of their head until the pin aligns with its reflection in the mirror. This ensures that both the pin and the measurement are viewed at the same angle.
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Correct Alignment: Finally, according to the view seen by the student, they should make sure that the pin does not create a parallax effect by ensuring it lines up with the correct reading directly below the pin.
Step 2
Explain what the student must do to determine E.
Answer
To determine the Young modulus E, the student should:
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Identify Variables: Choose the appropriate independent variable (mass m) and dependent variable (displacement y).
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Measure Displacement: Use the setup with the mass hanging from the steel strip to measure various displacements y at different masses. The mass can be varied in increments up to a total of 250 g, taking care to ensure that only one variable is changed at a time.
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Collect Data: Record the respective displacements in a data table, where various values of m correlate with the measured displacements y.
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Plot Graph: Plot a graph of y against m, which should yield a linear relationship. The gradient of this line can be used in the formula to calculate E.
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Analyze Results: Use the equation to solve for E, where L, w, and t are known constants from the setup. Make sure to consider any percentage errors in measurements.