I know that centrifugal force only "exists" when the reference frame is rotating. In this case, if there is centripetal force, there must also be centrifugal force so that bodies on the rotating frame will be motionless.
But if centrifugal force is a pseudo-force then why we can observe its effects outside of rotating frame? I mean if we start to spin a table with objects on it very fast, we can see the objects flung to different directions. Hence there must be acceleration outwards and we can observe it when our reference frame is outside of rotation. The centrifuge device is another example.
Best Answer
When objects fly off a spinning table, from an external reference frame they simply stop travelling in circles. At the point of "unsticking" they do not accelerate radially outwards from the centre of rotation but merely stop accelerating inwards; they continue in a straight line tangential to the circle and at right angles to the radial direction. Thus, no centrifugal force is present - indeed, it is the very absence of any force subsequent to breakaway which explains their behaviour.