A pellet of mass 8.8 g embeds itself in a wooden block of 450 g which is suspended by a light in-extensible string. After the collision the block reaches a max height of 0.63 m. Calculate the initial velocity of the pellet.

Max Gravitational Potential energy of combined mass:GPE = m x g x h= ( 0.0088 kg + 0.450 kg ) x 9.81 ms^-2 x 0.63 m = 2.84 J
Therefore Kinetic energy of the combined mass at the collision = 2.84 JKE = 1/2 x m x V^2V^2 = 2 x 2.84J / (0.0088 kg + 0.450 kg) = 12.38V = (12.38)^0.5 = 3.52 m/s
The momentum of the combined mass:p = m x V= 0.4588 kg x 3.52 m/s = 1.61 kg m/s
Therefore the initial momentum of the pellet = 1.61 kg m/sV = p / mV = 1.61 kg m/s / 0.0088 kg = 182.95