A long helix made of thin wire is held vertical. The radius and pitch of the helix are R and `rho` respectively. A bead begins to slide down the helix.
(a) Find the normal force applied by the wire on the bead when the speed of the bead is `upsilon`.
(b) Eventually, the bead acquires a constant speed of `v_(0)`. Find the coefficient of friction between the wire and the bead.

Answer

(a) `mg "cos"theta sqrt(1 + ((v^(2) "cos"theta)/(Rg))^(2)))`
(b) `("tan"theta)/(sqrt(1 + ((v^(2) "cos"theta)/(Rg))^(2)))` where `"tan"theta = (rho)/(2piR)`