Use the readings in Fig. 4.2 to determine $r_1$. Enter your answer for $r_1$ in the table in Fig. 4.3, and show your working.
Fill in the missing $x$ and $y$ values in the table in Fig. 4.3.
On the grid in Fig. 4.4, plot $y$ (y-axis) against $x$ (x-axis). Begin both axes at the origin $(0,0)$, then draw the straight line of best fit.
Work out the gradient of your line. Show your working and mark on the graph the values you select.
The copper cylinder’s mass $m$, in grams, is found from $m = 150 \times \text{gradient}$. Use this relation to calculate $m$ to the nearest gram.
Using Fig. 4.5, work out the volume $V$ of the copper cylinder.
Use your answers to (b)(iv) and (c) with $\rho = \frac{m}{V}$ to calculate the density $\rho$ of copper.
The density of copper found in (d) is slightly different from the accepted value. State one practical reason for this discrepancy.