You are Here: Home >< Physics

# AS Advancing Physics - Looking inside materials questions Watch

1. Here are some questions I am stuck on. Hope you can answer them.

Show that the pressure exerted by a 2.5kg brick when sitting on its largest face (area 20 x 10-3m2) is about 1.25kPa. Thus show that if the maximum compressive strength of common bricks is 20MPa, the maximum height of a stack of bricks, before the bottom gives way, is about 16km.

Show that a nylon fishing line of diameter 1mm requires energy of the order of 1mJ to fracture and that, assuming the average value for the tensile strength of nylon, this corresponds to a load of about 400N.

A piece of rubber 6cm long cut from a rubber band will easily extend to 7cm when supporting a small load. Bonds between atoms typically break when the distance between the atoms is increased by 1%. Show that the extension of the rubber cannot simply be due to stretching of the bonds between atoms.

Hooke's law states that extension is proportional to load F and is usually written F=kdeltax. The Young modulus E=stress/strain. Show that the Hooke's law constant k is related to the Young modulus E by the relationship k=EA/L
2. Could you take a look at the guidelines for posting questions here
http://www.thestudentroom.co.uk/wiki...ting_responses

In particular the following

... when posting include any progress you already have towards it. What we would not like you to do when posting is to post in a manner that suggests you want other people to do your work for you, which is also likely to lead to you not getting the responses you would like.
You need to
-show what attempt you've made and where you are stuck

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: March 31, 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
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.