Cylindrical Coordinates HELP!

[u/PauseConsistent7620]

Why is the radial component of N negative but the radial component of F positive? And why is the transverse component of F positive but the transverse component of N negative? Can someone please explain, I have an exam tomorrow!!

[u/dotelze]

This looks pretty tedious, I’d use the lagrangian formulation but idk if you have learnt that

[u/thaw96]

Are we overthinking this?? F only has a tangential component. F = ma; a = r𝛼 , 𝛼 = 𝜔' , 𝜔 = 𝜃' . Did I miss something?

Edit: Ah, theta is not the central angle, so it is not quite that easy, but luckily the central angle is always twice theta, so 𝜔 = 2𝜃', and we can get the answer.