physics (work shown)
posted by Sarah .
A 0.63-kg block is hung from and stretches a spring that is attached to the ceiling. A second block is attached to the first one, and the amount that the spring stretches from its unstrained length quadruples. What is the mass of the second block?
My work is as follows:
mg=kx Since k is unknown, I chose to use 1
My answer is incorrect. What am I doing wrong?