# Homework Help: Simple moment question

1. Oct 14, 2006

### Magic Mushroom

Hi, i'm having a little trouble with this simple question on moments and i'm wondering if anyone could help me out by giving me a suitable method.
http://www.aqa.org.uk/qual/gceasa/qp-ms/AQA-PHB1-W-QP-JUN05.PDF [Broken] that is the link and the question is 2.b.i. Please don't give me the answer just the method! :)

Last edited by a moderator: May 2, 2017
2. Oct 14, 2006

The sum of the moments of all forces acting on the bar must vanish (including the weight of the bar). Use that fact to obtain the reaction in the pivot.

Last edited by a moderator: May 2, 2017
3. Oct 14, 2006

### OlderDan

This will work for 2.b.i if the moments are calculated about some point other than the pivot. Perhaps the OP is having difficulty because questions 2.a has them thinking only of moments about the pivot.

Alternatively, once the weight of the beam is known from 2.a.iii the reaction in the pivot can be found by summing all the forces to get zero.

4. Oct 14, 2006