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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 during measurement, the student should place a mirror behind the ruler. By adjusting their position so that the pin's image in the mirror aligns with the actual pin, they can ensure that they are viewing the measurement at a perpendicular angle. This alignment minimizes any misreading due to the viewing angle.
Step 2
Explain what the student must do to determine E.
Answer
To determine the Young modulus E using the setup in Figure 5, the student should:
- Use a single steel strip of approximately 30 cm length, ensuring it is clamped securely at one end.
- Hang a mass m using a 50 g mass hanger at the free end of the strip, adding up to four additional 50 g slotted masses, ensuring that the total mass used varies as the independent variable.
- Measure the corresponding vertical displacement y of the strip for each mass added using the previously described method to avoid parallax error.
- Record all measurements systematically, ensuring that the width w is constant at about 1 cm and the thickness t is kept constant at approximately 1 mm.
- Plot a graph of y against m on a suitable Cartesian plane. The relationship will be linear, allowing the student to determine the gradient of the graph.
- From the derived equation rearranging it to find E gives: This formula will enable the student to calculate the modulus of elasticity for steel based on the recorded values.