Question SPM.1B.SL.TZ0.2
| Date | May Specimen-2023 | Marks available | [Maximum mark: 8] | Reference code | SPM.1B.SL.TZ0.2 |
| Level | SL | Paper | 1B | Time zone | TZ0 |
| Command term | Calculate, Discuss, Outline, Suggest | Question number | 2 | Adapted from | N/A |
A group of students investigate the bending of a plastic ruler that is clamped horizontally at one end. A weight W attached to the other end causes the ruler to bend. The weight is contained in a scale pan.
The students fix the length L of the ruler and vary W. For each value of W, the group measures the deflection d of the end of the ruler to which the weight is attached.
The group obtains the following repeated readings for d for one value of W.
The group divides into two subgroups, A and B, to analyse the data.
Group A quotes the mean value of d as 2.93 cm.
Group B quotes the mean value of d as 2.8 cm.
Discuss the values that the groups have quoted.
[2]
3 sf is inappropriate for A ✓
rejects trial 3 as outlier for B ✓
The variation of d with W is shown.
Outline one experimental reason why the graph does not go through the origin.
[1]
beam bends under its own weight / weight of pan
OR
specified systematic error in d ✓
Theory predicts that
where and are constants. The fundamental units of are m4 and those of are kg m−1 s−2.
Calculate and .
[2]
units of W : kg m s−2 ✓
work leading to and ✓
The ruler has cross-sectional area A = a × b, where a = (28 ± 1) mm and b = (3.00 ± 0.05) mm.
Calculate the percentage uncertainty in the value of A.
[2]
attempt to calculate fractional uncertainty in either a or b [0.0357, 0.0167] ✓
0.0357 + 0.0167 = 0.05 = 5 % ✓
Suggest an appropriate measuring instrument for determining b.
[1]
instrument (capable of reading to 0.05 mm) with reason related to resolution of instrument ✓
eg micrometer screw gauge, Vernier caliper, travelling microscope