Answers to AQA GCSE Calculating Spring Constant

Practice Questions

1.A material has a spring constant of 100N/m and a force of 25N is applied to increase its length. Calculate the extension.

F = ke

e = F/k

e = 25  / 100 N/m 

e = 0.25m

2.A spring is stretched from 5cm to 30cm and it has a spring constant of 40N/m. Calculate the force needed to stretch the spring

Convert length to m

5cm = 0.05m, 30cm = 0.3m

Extension = 0.3m-0.05m = 0.25m

F = ke

F = 40N/m x 0.25m = 10N

3. A spring is stretched by 50cm using a set force, this spring is replaced with another spring that has a value for its spring constant that is double the previous spring. Assuming the same force is applied, calculate the new extension. 

If the spring constant doubles, it needs twice as much force to cause the same change in length of spring. So, if the force is unchanged, then the extension will halve from 50cm to 25cm.