You are using a laboratory centrifuge to collect particles in a water-filled test tube. The test tube is completely full of the water. Calculate the time for particles to travel from the top to the bottom of the 10 cm long test tube. The centrifuge is rotating at 500 rpm and the top of the test tube is 5cm from the axis of rotation. You can assume the terminal velocity can be reached instantaneously and the test tube rotates horizontally. (particle density: 1.05g/cm^3 particle diameter: 10 micrometer water density: 1g/cm^3 and viscosity of water is 1 centipoise.