A very stiff spring (k=3470 N/m) is compressed from its relaxed length by 45.4 cm.
a. Calculate the amount of potential energy stored in the compressed spring.
b. The compressed spring is the launching mechanism of a big cannon. A large watermelon (mass =33.3 kg ) is loaded into the cannon, and the watermelon is launched horizontally, so that all of the spring's stored potential energy is converted into kinetic energy. Calculate the speed of the launched watermelon.