Answer:
The answer for the first question is: 3,000,000 N/m
The answer for the second question is: If the question was, "Which of the following is the best example of kinetic energy being transformed into potential energy?" then the answer is winding the spring on a toy car
Explanation:
For the first question: I have no explanation, I just got it right on my test so I thought i'd help you out.
For the second question: (i'll try to explain the best I can).
Kinetic energy = energy in motion
Potential energy = stored energy
so when winding the spring of a car you are using energy in motion (kinetic energy) to create stored energy (potential energy) that will be used to move the car. So it goes something like:
kinetic energy > potential energy > kinetic energy