Block 1 of mass \(M\) is held at rest on a frictionless inclined plane of angle \(\theta\). The center of mass of Block 1 is initially at a vertical height \(H\) above a frictionless horizontal surface. Block 2 of mass \(2M\) rests on the horizontal surface at the bottom of the incline. Further down the horizontal surface, a lightweight spring of spring constant \(k\) is attached to a rigid wall. Block 1 is released, slides down the incline, and collides with Block 2. The two blocks stick together and slide along the horizontal surface until they strike and compress the spring.