A bullet of mass 2 g travelling with a velocity of $500{\text{ms}}^{-1}$ is fired into a block of wood of mass 1 kg suspended from a string of 1m length. When the bullet penetrates the block of wood and comes out with a velocity of$100{\text{ms}}^{-1}$ , find the vertical height through which the block of wood will rise (assuming the value of g to be$10{\text{ms}}^{-2}$ )