Forces, movement, shape and momentum

A student investigates how the extension of a latex rubber strip varies with applied force.

Name three pieces of laboratory apparatus that the student needs to carry out this investigation.

[3]

For this investigation, identify which variable is:

[2]

Describe how the student can determine the extension of the rubber strip when a force of 15 N is applied.

[3]

The student obtains the following data during loading (adding weights) and unloading (removing weights):

(mm)1540.01234.0924.0614.036.000.0\begin{array}{|c|c|} \hline \textbf{Force (N)} & \textbf{Loading Extension (mm)} \\ \hline 0 & 0.0 \\ \hline 3 & 4.0 \\ \hline 6 & 10.0 \\ \hline 9 & 18.0 \\ \hline 12 & 28.0 \\ \hline 15 & 40.0 \\ \hline \end{array} \quad \begin{array}{|c|c|} \hline \textbf{Force (N)} & \textbf{Unloading Extension (mm)} \\ \hline 15 & 40.0 \\ \hline 12 & 34.0 \\ \hline 9 & 24.0 \\ \hline 6 & 14.0 \\ \hline 3 & 6.0 \\ \hline 0 & 0.0 \\ \hline \end{array}

Suggest two ways the student could improve the quality of the data collected (other than repeating and averaging).

[2]

The student concludes: "The latex strip is an elastic material and it obeys Hooke's law."

Discuss whether this conclusion is correct. You should support your argument using data from the tables.

[4]