posted by Jim .
A rifle fires a 2.25 10-2-kg pellet straight upward, because the pellet rests on a compressed spring that is released when the trigger is pulled. The spring has a negligible mass and is compressed by 8.37 10-2 m from its unstrained length. The pellet rises to a maximum height of 5.49 m above its position on the compressed spring. Ignoring air resistance, determine the spring constant.