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This is about an experiment with a retractable steel tape measure - AQA - A-Level Physics - Question 2 - 2018 - Paper 3
Question 2
This is about an experiment with a retractable steel tape measure. The tape measure is placed at the edge of the bench and about 1 m of the steel tape is extended ... show full transcript
Worked Solution & Example Answer:This is about an experiment with a retractable steel tape measure - AQA - A-Level Physics - Question 2 - 2018 - Paper 3
Step 1
Describe a suitable procedure the student could use to measure y.
Answer
A suitable procedure could involve measuring the vertical distance of the free end of the tape from the floor.
The student could use a meter ruler or a straight edge aligned vertically alongside the tape to measure the height of the free end of the tape over the bench, ensuring that it's measured perpendicular to the floor for accuracy.
Using a ruler, the height can be measured directly from the tape end to the secure point on the floor.
Step 2
Suggest why the student chose to make all measurements of x greater than 70 cm.
Answer
The student likely chose to measure all x values greater than 70 cm to ensure that the tape was sufficiently extended to reduce the error due to sagging or other physical distortions, and also to remain within the stable operational range of the tape measure.
Step 3
Determine n using Figure 8.
Answer
From Figure 8, the graph appears to be a straight line, indicating a relationship of the form y = Ax^n. Using the slope of the line obtained from best-fit analysis, if the slope is determined and represents n, we can then ascertain that the value of n is equivalent to that slope rounded to the nearest integer in the appropriate range.
Step 4
Explain how the numerical value of A can be obtained from Figure 8.
Answer
The numerical value of A can be extracted from the graph by evaluating the intercept on the y-axis. Since the linear relationship is transformed into log scale, the intercept corresponds to log(A). The exponential of the y-intercept will provide the actual numerical value of A. Thus, A can be calculated as follows: where 'y-intercept' is the point where the line crosses the y-axis.
Step 5
Estimate the order of magnitude of A.
Answer
To estimate the order of magnitude of A, select a row from Table 2, for instance, x = 132.4 cm and y = 61.2 cm. Using the relationship y = Ax^n with an assumed value for n, calculate A: A = rac{y}{x^n}. With n determined from earlier graph work, calculate A, and order of magnitude can be derived depending on A's value in scientific notation, indicating its scale.