Please help... Thank you

Question

The projectile, of mass m0, is fired into a large block (of wood or other material) of mass M, which is suspended like a pendulum. (Usually, M is somewhat greater than m0.) As a result of the collision, the pendulum and projectile together swing up to a maximum height.

Part A Derive a formula for the fraction of kinetic energy lost, ΔK/K, in terms of m0 and M for the ballistic pendulum collision. Express your answer in terms of the variables m0 and M

Answer 1

Apply conservation of momentum for the inelastic collision: m₀v₀ = (m₀+m)v where v is the velocity of the block/bullet system. (solve for v in terms of v₀, m₀, and m.)

K₀ = 1/2 m₀v₀² K = 1/2(m+m₀)v²

plug in for v (don't forget to square everything) and do the algebra for (K-K₀)/K₀