Turn on thread page Beta
    • Thread Starter
    Offline

    19
    ReputationRep:
    How do i solve moments for a square or rectangle like this:

    mirror of mass 24kg is supported by two screws 80cm apart, placed at the top. One screw come off and is going to be replaced. A helper holds the mirror with force {F } 120cm below the level of the screws. I have to find F, but i dont know how to find moments when it's a square or rectangle

    Attachment 699146
    • Community Assistant
    • Study Helper
    Offline

    20
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by joyoustele)
    How do i solve moments for a square or rectangle like this:

    mirror of mass 24kg is supported by two screws 80cm apart, placed at the top. One screw come off and is going to be replaced. A helper holds the mirror with force {F } 120cm below the level of the screws. I have to find F, but i dont know how to find moments when it's a square or rectangle

    Attachment 699146
    It doesn't matter what the shape is, you know the mirror is in equilibrium which means that if you take moments about any point you should get 0.

    Try taking moments about the black screw and post your working/thoughts if you get stuck.
    • Thread Starter
    Offline

    19
    ReputationRep:
    (Original post by Notnek)
    It doesn't matter what the shape is, you know the mirror is in equilibrium which means that if you take moments about anypoint you should get 0.

    Try taking moments about the black screw and post your working/thoughts if you get stuck.
    I'm so glad people like you are on TSR, my working:

    F(120)=24g(40)

    F=\dfrac{24g(40)}{120}

    F=78.4N

    I got the correct Answer. TY
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: October 27, 2017
The home of Results and Clearing

1,349

people online now

1,567,000

students helped last year

University open days

  1. Bournemouth University
    Clearing Open Day Undergraduate
    Fri, 17 Aug '18
  2. University of Bolton
    Undergraduate Open Day Undergraduate
    Fri, 17 Aug '18
  3. Bishop Grosseteste University
    All Courses Undergraduate
    Fri, 17 Aug '18
Poll
Will you be tempted to trade up and get out of your firm offer on results day?
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.