You are Here: Home >< Maths

# Unsure about force diagram - rigid bodies Watch

1. Hi, I'm stuck on a force diagram because I'm not sure how a hinge impacts it. The question itself can be found here http://i.imgur.com/KMCXnla.png.

I've split into to separate diagrams each with a normal reaction to the floor; the weight coming from the middle of the ladder and the tension from the string. Is there a reaction force from the hinge? Where would it point?

Any help would be appreciated a lot.
2. (Original post by Heywhatsgood)
Hi, I'm stuck on a force diagram because I'm not sure how a hinge impacts it. The question itself can be found here http://i.imgur.com/KMCXnla.png.

I've split into to separate diagrams each with a normal reaction to the floor; the weight coming from the middle of the ladder and the tension from the string. Is there a reaction force from the hinge? Where would it point?

Any help would be appreciated a lot.
Yes, there is a reaction at the hinge. How do you know that? Becasue if the hinge wasn't there, the ladders would fall flat.

Best way, IMO to look at the hinge is to break the reaction down into horizontal and vertical components.

Considering the horizontal.

If the hinge wasn't there which way would the ladder fall? Right or left? Reaction at hinge must be in the opposite direction.

Considering the vertical.

This is a little trickier. By symmetry the vertical component must be the same for each of the ladders (in magnitude and direction). But since the hinge isn't moving the vertical component for one ladder must be equal and opposite to the vertical component on the other ladder. There is only one value for the vertical force that satisfies these two properties. Any thoughts?

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: May 6, 2016
Today on TSR

### Falling in love with him

But we haven't even met!

### Top study tips for over the Christmas holidays

Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

## Groups associated with this forum:

View associated groups
Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• 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

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