A 2.10-kg block is suspended from a spring with a spring constant of 280.0 N/m. A 0.070-kg bullet is fired into the block from directly below with a speed of 220.0 m/s and is embedded in the block. Find the amplitude of the subsequent motion.
-What fraction of the original kinetic energy of the bullet appears as mechanical energy in the system of block-spring-bullet?
we are learning about the oscillations and energy. For this question i'm thinking I would need to use E= Kinetic energy + potential energy.... (1/2)KA2=(1/2)mv2 + (1/2)Kx2
but I don't know what to do to get started, I am soo lost!