A spider spring of a spring balance is 25cm long when 5N weight hang on it and 30cm long when the weight is 10N what is the length of the spring it is weigth is 3N assuming hooke's law is obeyed?

2 answers

k= changforce/changlenght=(10-5)/(30-25)=1N/cm
so at 3N, it will be 2cm shorter than 25cm.
Good