A plank 2.00 cm thick and 16.7 cm wide is firmly attached to the railing of a ship by clamps so that the rest of the board extends 2.00 m horizontally over the sea below. A man of mass 71.6 kg is forced to stand on the very end. If the end of the board drops by 5.60 cm because of the man's weight, find the shear modulus of the wood.