# Natural length of spring

#### TG3

1. Homework Statement
If 6 J of work is needed to stretch a spring from 10 cm to 12 cm, and another 10 J is needed to stretch it from 10 to 12 cm, what is the natural length of the spring?

2. Homework Equations
W=FD
Hooke's Law

3. The Attempt at a Solution
Honestly, I stare at this problem and am at a loss as to where to start, and there are no examples in the book like this. Obviously I'm not asking for answers because I know the rules here, we're supposed to show effort; but if someone gave me some starting help it would be much appreciated.

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#### LowlyPion

Homework Helper
1. Homework Statement
If 6 J of work is needed to stretch a spring from 10 cm to 12 cm, and another 10 J is needed to stretch it from 10 to 12 cm, what is the natural length of the spring?

2. Homework Equations
W=FD
Hooke's Law

3. The Attempt at a Solution
Honestly, I stare at this problem and am at a loss as to where to start, and there are no examples in the book like this. Obviously I'm not asking for answers because I know the rules here, we're supposed to show effort; but if someone gave me some starting help it would be much appreciated.
Consider

PE = 1/2*k*x2

#### Doc Al

Mentor
1. Homework Statement
If 6 J of work is needed to stretch a spring from 10 cm to 12 cm, and another 10 J is needed to stretch it from 10 to 12 cm, what is the natural length of the spring?
Looks like you have a typo in the problem statement.

Hint: Call the unstretched length of the spring L. How do you determine the work done to stretch a spring? (What's the expression for spring potential energy?)