Read the distance $l$ on Fig. 1.1 to the closest millimetre. Note your value.
Fig. 1.1 is drawn to a scale of one-eighth of the full size. Work out the true length $L$ of the pendulum from the support point to the centre of the pendulum bob.
Calculate $T_{10}$, the mean time for 10 full oscillations. Give your answer to 2 significant figures.
Finish Table 1.1 with the result from (b)(i). You will need to work out $T$ and $T^2$.
Explain why the student times 10 complete oscillations instead of 1 complete oscillation.
On the grid in Fig. 1.2, draw a graph of $T^2$ (y-axis) against $L$ (x-axis). Begin both axes at the origin $(0,0)$. Draw the straight line of best fit.
Determine the gradient $G$ of your line. Show your working and mark on the graph the values you use.
Theory indicates that the gravitational field strength $g$ is given by: $g = \frac{0.39}{G}$. Use this formula together with your value of $G$ in (b)(v) to calculate $g$.
Compare the value of $g$ you found in (b)(vi) with the accepted value of $10\,\text{N kg}^{-1}$. Say whether the two values are in agreement and explain your answer.