A cart of mass 5 kg is held on the ramp at a height of 1.8 m. Another cart of mass 5 kg is on a frictionless surface sitting next to a spring with spring constant 110 N/m. At some instant, the first cart starts sliding down and hits the second cart. If the collision between the carts is elastic in nature, find the compression in the spring caused by the second cart. [limit your answers within one decimal places].