Physics 9702/31 — October/November 2021

● Slide the loop of a spring onto a wooden rod. Fix the loop of the spring in the middle of the wooden rod with a clip, as shown in Fig. 1.1.

● Use half of the adhesive putty to fix four $10\text{ g}$ masses to the wooden rod as shown in Fig. 1.2.

● Adjust the positions of the masses until the distance between the masses is approximately $22\text{ cm}$. The masses should each be approximately the same distance from the clip, as shown in Fig. 1.2.

● Clamp the loop at the top of the spring between two small wooden blocks.

● Arrange the apparatus as shown in Fig. 1.3.

● Adjust the position of the clip until the rod balances approximately parallel to the bench.

● The distance between the masses on the wooden rod is $x$, as shown in Fig. 1.3.

Measure and record $x$.

$x$ = ______

● Using the other wooden rod, set up a second set of apparatus as shown in Fig. 1.3.

● The distance between the masses on this wooden rod is $p$.

Adjust the position of the masses until the value of $p$ is approximately $18\text{ cm}$.

● Measure and record $p$.

$p$ = ______

● Move the apparatus until the two rods are close to each other and in line as shown in Fig. 1.4.

● Gently press the rods down at end X and end P.

● Release the ends at the same time. The ends will oscillate as shown in Fig. 1.5.

● Watch the oscillations. X and P move in and out of phase.

● Look at P. Count the number $n$ of oscillations made by P from release until both ends are back in phase.

$n$ = ______

Change $p$ in the range $14.0\text{ cm} \leq p \leq 20.5\text{ cm}$ and repeat (c) until you have six sets of values of $p$ and $n$.

Keep distance $x$ constant.

Record your results in a table. Include values of $\frac{1}{p}$ and $\frac{1}{n}$ in your table.

Record the values of $\frac{1}{n}$ to three significant figures.

It is suggested that the quantities $n$ and $p$ are related by the equation

$$\frac{1}{n} = \frac{A}{p} + B$$

where $A$ and $B$ are constants.

Using your answers in (e)(iii), determine the values of $A$ and $B$.
Give appropriate units.

$A$ = ______
$B$ = ______