Question
- Leaving Cert. Physics (Higher) 2017: Section A Q1
- Back to the question >
Answer
A student investigated the relationship between the period and the length of a simple pendulum. The student measured the length l of the pendulum which was then allowed to swing about a fixed point and through a small angle. The time t for 40 oscillations was measured. This procedure was repeated for different lengths of the pendulum.
The following data were recorded.
Why did the student use a small angle?
The motion of a pendulum is most easily understood as being simple harmonic motion but this is a valid understanding only when the angle of oscillation is small.
How did the student ensure that the pendulum was suspended from a fixed point?
The student would have suspended the pendulum from a split cork fixed to a retort stand, as shown.
Between which points was the length of the pendulum measured?
The length would have been measured from the bottom of the cork to the centre of gravity of the pendulum bob, as shown.
Which t value is most accurate? Explain your answer.
The t value most likely to be accurate is that for a length of 90 cm. This is because it is the largest value and therefore, the percentage error will be at its lowest.
Draw a suitable graph to show the relationship between the length of a pendulum and its period.
Use your graph to calculate g, the acceleration due to gravity.
