How much force is required to turn the front wheel of a 4 wheel robot that weighs 200lb. Assume the wheel is 6inches wide, has a diameter of 12 inches (rubber). I would like to know how much force is required to turn a single wheel left or right when it is in stationary (non-moving) position. If anyone can help, can you please break down the math? I would like to be able to scale this down (or up) to explore various weight sizes.