Question 18N.3.SL.TZ0.1
| Date | November 2018 | Marks available | [Maximum mark: 10] | Reference code | 18N.3.SL.TZ0.1 |
| Level | SL | Paper | 3 | Time zone | TZ0 |
| Command term | Determine, Draw, Explain, State, Suggest | Question number | 1 | Adapted from | N/A |
In an investigation to measure the acceleration of free fall a rod is suspended horizontally by two vertical strings of equal length. The strings are a distance d apart.
When the rod is displaced by a small angle and then released, simple harmonic oscillations take place in a horizontal plane.
The theoretical prediction for the period of oscillation T is given by the following equation
where c is a known numerical constant.
State the unit of c.
[1]
✔
Accept other power of tens multiples of , eg: .
A student records the time for 20 oscillations of the rod. Explain how this procedure leads to a more precise measurement of the time for one oscillation T.
[2]
measured uncertainties «for one oscillation and for 20 oscillations» are the same/similar/OWTTE
OR
% uncertainty is less for 20 oscillations than for one ✔
dividing «by 20» / finding mean reduces the random error ✔
In one experiment d was varied. The graph shows the plotted values of T against . Error bars are negligibly small.
Draw the line of best fit for these data.
[1]
Straight line touching at least 3 points drawn across the range ✔
It is not required to extend the line to pass through the origin.
Suggest whether the data are consistent with the theoretical prediction.
[2]
theory predicts proportional relation «, slope = Td = = constant » ✔
the graph is «straight» line through the origin ✔
The numerical value of the constant c in SI units is 1.67. Determine g, using the graph.
[4]
correctly determines gradient using points where ΔT≥1.5s
OR
correctly selects a single data point with T≥1.5s ✔
manipulation with formula, any new and correct expression to enable g to be determined ✔
Calculation of g ✔
With g in range 8.6 and 10.7 «m s−2» ✔
Allow range 0.51 to 0.57.