Q1. A rubber band has a spring constant of 68 N per metre, calculate the force which needs to be applied to extend this rubber band from its rest length of 50 cm to a new length of 75 cm.


This is a basic application of the force equation, note the fact that the extension is given in centimetres so this will need to be corrected first. The extension is 0.25 m (25 cm), the spring constant is already given in the so we can simply plug the values into the equation and come up with an answer:



Q2. A spring is compressed from its rest position of 16 cm, down to 12 cm when a force of 3.2 N is applied to it. From this information calculate the spring constant "k"


The formula needs to be rearranged in terms of the spring constant "k", the compression values need to be changed from centimetres to metres then the calculation can go ahead.






Q3. A spring with a spring constant "k" of 136 N per metre is compressed to 5cm by the application of a force of 34 N. What was the original length, in cm of the spring?



If the EXTENSION / COMPRESSION is 25cm the spring must have started off at 30cm.



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