You are Here: Home >< Maths

# M2 body force diagram help? Watch

1. http://papers.xtremepapers.com/Edexc...elphis%206.pdf

In question 5 a) it asks to draw the forces. I'm know concerned about the force acting on the hinge. I know the reaction force has 2 components the vertical (or parallel to the wall) which is the force of friction and the horizontal (or perpendicular to the wall) which is the normal reaction. Since the question here states the rod is smoothly hinged i THINK there is no vertical force am I right? if so, what balances out the weight?
thanks
2. A smooth hinge just means that it can rotate easily - just like the 'smooth pulleys' you probably met in M1. There are therefore both horizontal and vertical components of the force exerted on the rod by the hinge (and on the hinge by the rod) (note: not friction, the rod is HINGED to the wall, not resting on a rough wall).
3. (Original post by dragonkeeper999)
A smooth hinge just means that it can rotate easily - just like the 'smooth pulleys' you probably met in M1. There are therefore both horizontal and vertical components of the force exerted on the rod by the hinge (and on the hinge by the rod) (note: not friction, the rod is HINGED to the wall, not resting on a rough wall).
so to get this straight the vertical force isn't friction and it is existing if even if it is smoothly hinged am I correct?
Plus what about the horizontal component im going to assume it is not the normal reaction force or what? thanks again
4. (Original post by >>MMM<<)
so to get this straight the vertical force isn't friction and it is existing if even if it is smoothly hinged am I correct?
Plus what about the horizontal component im going to assume it is not the normal reaction force or what? thanks again
Yes - it may help you to visualise holding a door (ok, a small door...) in your hand by the hinge, with the rope attached as in the picture. Try to imagine where the door would fall if you suddenly let go - this is the direction in which the force of the door on your hand is going. As every force has an equal and opposite reaction force, your hand must therefore be exerting a force in the exact opposite direction in the door - i.e. sort of diagonally.

There is actually just one force (the normal force), but you tend to split it into horizontal and vertical components to make calculations easier.
EDIT: maybe it's sort of two forces... I tend to just label them N (perpendicular to the surface, so in this case horizontally) and F (which could stand for friction if it was just resting on a rough surface, or just force (as in this case)). The examiner can decide what they mean... (I doubt you will be asked 'what is the normal force' anyway...)

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: April 12, 2013
Today on TSR

### What is the latest you've left an assignment

And actually passed?

### Simply having a wonderful Christmas time...

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

## Make your revision easier

### 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

Can you help? Study help unanswered threads

## 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.