Angular velocity and acceleration

[enger]

Homework Statement

the spring oa is fixed from one end o to the bottom of a vertical circular smooth tube and from its other end to a slider a of mass m which can slide smoothly along the tube initially started from rest at a .
find :
i) angular velocity
II) angular acceleration at any angle
iii)angle at which the slider comes to instantaneous rest

Homework Equations

Conservation of energy and netwen 2nd law

1/2 mv^2 + 1/2 Kx^2 + mgh=1/2 mv^2 + 1/2 Kx^2 + mgh

The Attempt at a Solution

fn=fan = mrΘdot = n-mgcosΘ +kx
ft=f at = mrΘt double dot = -mgsinΘ

Θ(dot)^2 = 2mgcosΘ + 2gr

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i think i made a mistake & hope someone can help with this situation

 

[NascentOxygen]

I'd like to see your working for your attempted solution. The fact that you have kx appearing in your expression for f_n but not adding a component to f_t suggests that you are viewing the spring's force as directed towards the circle's centre. It isn't.