Two equal masses m are connected by an elastic string that acts like an ideal spring with spring constant k and unstretched length l. The two masses are hung over a frictionless pulley. What is the total length of the string at equilibrium? (Diagram not necessarily to scale.)
Answer Choices
A. 2 m g / k
B. l+m g / k
C. l+m g / 2 k
D. l+2 m g / k
E. There is not enough information to decide.
