The particular situation is below: "For the system shown in the attached image, find the force required to prevent the mass m2 from descending. Use the values of m1 = 5.25 kg, m2 = 6.50 kg and m3 = 2.500 kg. Assume that all surface are frictionless and that the ropes do not stretch. (Also, in the figure, assume that mass m2 is flush against m1.) " My first approach is to solve it via centripetal force by assuming that the rope will spin the system in a circle. This will result in a frictional force acting on m2 from m1 upwards against gravity. But how is that possible if all surfaces are frictionless as the question states? Thank you for your help!