Physics 9702/51 — October/November 2020

A student investigates a spring of width $w$ made from a metal wire, as shown in Fig. 1.1.

The student constructs several springs, each made from a metal wire of different cross-sectional area $A$. The student investigates how the extension $x$ of each spring varies with $A$ when a load of mass $m$ is applied.

It is suggested that the relationship between $x$ and $A$ is

where $g$ is the acceleration of free fall, $\rho$ is the density of the metal, $N$ is the number of turns of wire in the spring and $\gamma$ and $n$ are constants.

Design a laboratory experiment to test the relationship between $x$ and $A$.
Explain how your results could be used to determine values for $\gamma$ and $n$.

You should draw a diagram, on page 3, showing the arrangement of your equipment. In your account you should pay particular attention to:

• the procedure to be followed
• the measurements to be taken
• the control of variables
• the analysis of the data
• any safety precautions to be taken.