With the recent resurgence of vinyl records you decide to dig your old turntable out of the closet. It actually still works, and you note it spins up nicely to exactly 33 rpm (revolutions per minute) once it is set upon a level surface. As it spins at that speed, a fly (mass = 12 milligrams) lands on the spinning portion, exactly 3 cm from the center axis, and begins to walk radially outward at 2.0 cm/sec.
Assuming there is enough friction between the fly and the turntable to prevent any slipping, describe all the external (i.e. non-inertial) forces acting on the fly, and identify in which direction each force acts. If any of these forces are a combination of two or more physical principles, also list those.
Bonus: The magnitudes of most of these forces can be calculated from the information provided, but some cannot. Which ones cannot be calculated and why?