# Physics - Young's Modulus

> Source: https://ollybritton.com/notes/a-level/physics/topics/youngs-modulus/ · Updated: 2021-03-29 · Tags: physics, materials, school, year-1

## Flashcards
##### What is a loading and unloading curve??
A graph that shows how extension varies with force as a material is being stretched and released.

##### ![PHOTO LOADING UNLOADING RUBBER BAND](loading-unloading-rubber-band.png) Why is there a difference between the loading and unloading curves for an elastic band??
More work is done stretching (loading) the elastic band than releasing (unloading) it.

##### ![PHOTO LOADING UNLOADING RUBBER BAND](loading-unloading-rubber-band.png) What is the loop formed between the unloading and loading curves called??
A hysteresis loop.

##### What is tensile stress??
The force applied per unit cross-sectional area of a material.

##### What is the formula for tensile stress??
$$
\sigma = \frac{F}{A}
$$

##### What are the units for tensile stress??
Pascals or $Nm^{-2}$.

##### What is tensile strain??
The ratio of the original length of a material to the extension.

##### What is the formula for tensile strain??
$$
\epsilon = \frac{x}{L}
$$

##### What are the units for tensile strain??
It's a ratio, so it has no units.

##### ![PHOTO STRESS-STRAIN GRAPH](stress-strain-graph.png) In simple terms, what does this graph show??
How much a force per unit area will extend an object.

##### ![PHOTO STRESS-STRAIN GRAPH](stress-strain-graph.png) What does $P$ represent??
The limit of proportionality.

##### ![PHOTO STRESS-STRAIN GRAPH](stress-strain-graph.png) What does $E$ represent??
The elastic limit.

##### ![PHOTO STRESS-STRAIN GRAPH](stress-strain-graph.png) What do $Y_1$ and $Y_2$ represent??
The yelid points.

##### ![PHOTO STRESS-STRAIN GRAPH](stress-strain-graph.png) What does $UTS$ represent??
The ultimate tensile strength.

##### What is the Young's modulus of a material??
The ratio of stress to strain for a material.

##### How can you work out the Young's modulus from a stress-strain graph??
It's the gradient of the initial linear region.

##### What's the formula for the Young's modulus??
$$
E = \frac{\sigma}{\epsilon}
$$

##### What are the units for the Young's modulus??
Pascals or $Nm^{-2}$.

### 2021-06-29
##### What is the UTS of a material??
The maximum stress a material can withstand before fracture.

### 2021-09-19
##### What is true about the breaking stress of different objects made from the same material??
It is the same.

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