A pendulum with a light rigid rod

[Leonidu]

Homework Statement

The pendulum with a light rigid rod l has a mass m attached to it's end. It is put in a horizontal position and released from rest. At what angle grom the vertical will the tension in the suspension equal to the weight in magnitude?

Homework Equations

The Attempt at a Solution

the answer should be 71 deg , but I have no idea how to solve it

 

[tiny-tim]

Welcome to PF!

Hi Leonidu! Welcome to PF!

Use conservation of energy to find the speed, then use F_total = ma …

what do you get? ​