Finding the force exerted by the pivot (MOMENT OF FORCE)

This is an example question how to find the force exerted by the pivot in a system that is in equilibrium/balance.

[zeno-fx]

hey man, love the videos. Keep on grinding 🎉

[JadenForbes]

A uniform 100 kg log 20m long rest on two trestles one of which is 7m from one end while the other is directly under the other end. A boy of mass 60 kg stands over the first trestle and walks slowly towards the end nearer to him. How far will he get before the log becomes unstable?
Can u work out this question

[edutecharena]

Pls what did u use to create the video .I mean the software use for writing

[tafadzwamazhura]

What if there is an unknown on 10 Newton

[edutecharena]

How can I create tutorial video like this

[juliakubaty]

Does anybody know why you only add the forces together instead of adding the torques

[Basic-Tron]

MY brother is a fake hacker and I made him watch this video! HAHAHAHHA. Fool