A horizontal spring is compressed a distance of 0.4 meters by a block of mass 10 kg. Assume that there is no friction between the block and the floor. If the spring has a spring constant of 500 N/m then how fast (magnitude of the velocity) is the block launched after leaving the spring? Write your answer down in units of meters per second (m/s), but only write down the number part of your answer.

A horizontal spring is compressed a distance of 0.4 meters by a block of mass 10 kg. Assume that there is no friction between the block and the floor. If the spring has a spring constant of 500 N/m then how fast (magnitude of the velocity) is the block launched after leaving the spring? Write your answer down in units of meters per second (m/s), but only write down the number part of your answer.