A 10cm spring is hung from a clamp stand. With 1N of force it measures 12.2cm long and with 3N of force it measures 16.4cm long.
Estimate the stiffness of the spring

0.48 N/cm

Explanation:

The original length is 10cm so with a force of 10cm, the extension will be 12.2-10=2.2 cm when force of 1N is exerted. Similarly, with a force of 3N, the extension is 16.4-10=6.4cm

The slope will be given by change in force/ change in extension and this is equivalent to the stiffness.

Change in force is 3-1=2 N

Change in exgension is 6.4-2.2=4.2 cm

The slope will be 2/4.2=0.4761904761904 N/cm

Rounded off, the slope is 0.48 N/cm and this is the stiffness of the spring.