Terminal Velocity Steel Ball Bearing in Oil

[jldavid]

A 1.5-mm-diameter steel ball bearing (7830 kg/m^3) is dropped into a tank of SAE 30 oil. What is its terminal velocity?

The density of oil is 917kg/m^3, and the viscosity of oil is 0.26kg/(m*s).

Help is much appreciated!

 

[suspenc3]

What have you tried so far?

Where are you stuck?

 

[jldavid]

Force of drag = 1/2 * (density of fluid) * (area of sphere) * v^2 * (coefficient of drag)
Force of drag = 3 * pi * (coefficient of fluid) * (diameter of obj) * v

Coefficient of drag = 24 / (Reynolds number)

Reynolds number = (density of fluid * velocity of fluid * chracteristic length)/(viscosity of fluid)

When I combine the equations, v cancels out so I cannot solve for it. Is there another equation I should be using?