A platform is suspended by four wires at its corners. The wires are 3m long and have a diameter of 2.00 mm. Young's modulus of the material of the wire is $1.8 \times 10^{11} \mathrm{Nm}^{-2}$. How far will the platform drop due to the elongation of the wires if a 50kg load is placed at the centre of the platform?