In an experiment to determine the acceleration due to gravity, a student set up a simple pendulum of length 300 mm - Leaving Cert Physics - Question 1 - 2021

(a) Label the fixed point of suspension as the point where the string is anchored. (b) Mark the distance l as the length of the string from the fixed point to the midpoint of the bob.

Measuring the time for 20 oscillations helps to obtain a more accurate average time. Individual oscillation measurements can be influenced by timing errors and variations in the start and stop timing. By averaging over multiple oscillations, these random errors are minimized, leading to a more reliable determination of the oscillation period.

To graphically represent this data:

• Plot the length l on the x-axis against the square of the time per oscillation,
• Calculate the period for one oscillation by dividing the total time for 20 oscillations by 20 ( ext{period} = rac{t}{20}).
• Plot the values of l on the x-axis and the corresponding values of $( ext{period})^2$ on the y-axis.
• Draw a line of best fit through the plotted points to determine the slope, which will be used in the next step.

From the slope of the graph, we have: ext{slope} = rac{g}{4 ext{π}^2} To find g, rearrange the equation: $g = ext{slope} imes 4 ext{π}^2$ Substituting the slope value from the graph will yield the acceleration due to gravity g. Approximate value: $g ext{ is approximately } 9.8 ext{ m/s}^2$.