1. The problem statement, all variables and given/known data If a person holds a 30cm spring and compress on it with a force of 100 N (where k = 1000 N/m), by how much is the spring shortened. 2. Relevant equations Hooks ' Law: F = -k* deltaX 3. The attempt at a solution The answer for this is 10 cm: 10 = -1000 * deltaX Why doesn't the length of the original spring matter here? Also, how does the "-" sign affect Hook's Law here in this problem.