The observation and its tabulation were well handled by most responding candidates. However, the evaluation of Log L and Log T to the nearest decimal places was poorly tackled.
The plotting of the graph of log T against Log L was poorly handled. Evaluation of slope and determination of intercept on the vertical axis was fairly attempted. Candidates were able to state the precautions correctly in acceptable language.
The part b was fairly handled by most responding candidates as they were able to define simple harmonic motion but could not satisfactorily deduce the value of L from the graph when t = 12s probably because of the Logarithm involved.
In part (a) candidates are expected to:
- Measure and record five values of L to at least 1 d.p. and in trend.
Trend: As L increases, t, decreases
- Evaluate five values each of T, log L and log I to at least 3 s.f.
- Record data in composite table
- Plot five point, correctly using reasonable scales and distinguished axes
- Draw line of best fit.
- Determine the intercept on the vertical axes and the slope of the graph using large
right-angled triangle.
State any two of the following precautions in acceptable language.
- Ensured supports of pendula were rigged
- Avoided parallax error on meter rule/stop watch
- Zero error was noted and corrected on metre rule/stop watch/clock
- Ensured smooth and regular oscillations in a horizontal plane
- repeated readings shown on table
Part b expected answer are:
- Simple harmonic motion is the motion of a body whose acceleration is always directed towards a fixed point and is proportional to the displacement from the fixed point.
- T = = 1.2 secs
Log 1.2 = 0.079
0.079 shown on graph with corresponding log L read
L correctly determined.
