A spring with a spring constant, k, in a spring-loaded gun is compressed a distance, x, and shoots a marble of mass, m, straight up into the air to a maximum velocity, v, and maximum height of 4.0meters. The spring is then replaced by a different spring with 3k and stretched 0.5x. Find... a.) the maximum velocity using the original spring. b.) the original spring constant in terms of m and x (no units) c.) the maximum height of the same marble using the new spring. d.) the maximum velocity of the same marble using the new spring