Explain why this is not the most suitable way to assemble one stand, boss and clamp to support a heavy rod.
In the space to the right of Fig. 1.1, make a sketch of a better arrangement for assembling this apparatus.
Draw on Fig. 1.2 to indicate how the apparatus is used.
Explain how he can decide that the rod is horizontal.
Describe how the student can check that end A of the metre rule is directly above the 0 cm end of the half-metre rule.
The metre rule is shifted left until end A is above the 10 cm mark on the half-metre rule. It is then let go. As the metre rule oscillates, the amplitude gets smaller. The student counts the number $N$ of swings until end A no longer goes past the 5 cm mark on the half-metre rule. He repeats this a number of times, and the results are listed below. 53, 55, 52, 51, 53 Calculate $N_{av}$, the mean value of $N$. Give your answer to 2 significant figures.
The student is given one square piece of card with side $l$. He fastens the centre of the card to end A of the metre rule using a small piece of Blu-tack, as shown in Fig. 1.4.
Complete Fig. 1.5 by entering your value of $N_{av}$ from (c)(ii) for $l = 0$.
On Fig. 1.6, plot $l / \text{cm}$ on the $y$-axis against $N_{av}$ on the $x$-axis. Begin the axes at $(0,0)$ and draw a smooth curve of best fit.
The graph indicates that when $l$ gets smaller, $N_{av}$ gets larger. Two quantities $x$ and $y$ are inversely proportional if they satisfy the equation $x = \frac{k}{y}$, where $k$ is a constant. Using two pairs of values from the graph, show that $N_{av}$ is not inversely proportional to $l$.
Suggest why the student begins with $l = 19\,\text{cm}$ and then reduces $l$, instead of beginning with $l = 3\,\text{cm}$ and then increasing $l$.