A spring (k = 600 N/m) is placed in a vertical position with its lower end supported by a horizontal surface. A 2.0 kg block that is initially 0.40 m above the upper end of the spring is dropped from rest onto the spring. What is the kinetic energy of the block at the instant it has fallen 0.50 m (compressing the spring 0.10 m)? The acceleration due to gravity is 9.80 m/s