Deformation is a change in the size or shape of a body caused by forces acting on it.

What is the difference between tensile forces and compressive forces?

Tensile forces act to increase the length of a body Compressive forces act to reduce the length of a body

Define natural length .

The natural length of a spring is its length when no force is applied.

How is the extension of a spring calculated?

Extension = extended length − natural length

Define limit of proportionality .

The limit of proportionality is the point on a force-extension graph beyond which force and extension are no longer directly proportional .

A force-extension graph consists of a linear region followed by a .......... region.

A force-extension graph consists of a linear region followed by a non-linear region.

True or False? Beyond the limit of proportionality, a spring still obeys Hooke's law.

False. Beyond the limit of proportionality , force and extension are no longer directly proportional , so the spring no longer obeys Hooke's law .

Hooke's law states that a material's extension is directly proportional to the applied force (load), while it behaves elastically.

What shape is the force-extension graph of a material obeying Hooke's law?

A straight line through the origin

Define the spring constant .

The spring constant , k , is the force per unit extension up to the limit of proportionality; its SI unit is N m -1 .

How can the spring constant be found from a force-extension graph?

The spring constant, k , is the gradient of the linear part of a force-extension graph.

A stiffer spring has a .......... value of spring constant.

A stiffer spring has a larger value of spring constant.

Define ultimate tensile stress .

The maximum force per original cross-sectional area a wire can support before it breaks.

What does the gradient of a stress-strain graph represent?

The Young modulus of the material.

Why is a wire's diameter measured at several points along its length in the Young modulus experiment?

To reduce uncertainty in the cross-sectional area, by calculating an average diameter .

In the Young modulus experiment, the independent variable is the .......... and the dependent variable is the extension.

In the Young modulus experiment, the independent variable is the load and the dependent variable is the extension.

True or False? Strain has the same units as stress, pascals (Pa).

False. Strain is a ratio of two lengths, so it is dimensionless and has no units; stress is measured in Pa .

A LevelPhysicsCambridge (CIE)Flashcards6. Deformation of SolidsStress & Strain

Stress & Strain (Cambridge (CIE) A Level Physics): Flashcards

Exam code: 9702

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FrontExtension & Compression
Define deformation.
FrontExtension & Compression
What is the difference between tensile forces and compressive forces?
BackExtension & Compression
Tensile forces act to increase the length of a body
Compressive forces act to reduce the length of a body

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Cards in this collection (22)

Define deformation.
Deformation is a change in the size or shape of a body caused by forces acting on it.
What is the difference between tensile forces and compressive forces?
- Tensile forces act to increase the length of a body
- Compressive forces act to reduce the length of a body
Define natural length.
The natural length of a spring is its length when no force is applied.
How is the extension of a spring calculated?
Extension = extended length − natural length
Define limit of proportionality.
The limit of proportionality is the point on a force-extension graph beyond which force and extension are no longer directly proportional.
A force-extension graph consists of a linear region followed by a .......... region.
A force-extension graph consists of a linear region followed by a non-linear region.
True or False?
Beyond the limit of proportionality, a spring still obeys Hooke's law.
False.
Beyond the limit of proportionality, force and extension are no longer directly proportional, so the spring no longer obeys Hooke's law.
Define Hooke's law.
Hooke's law states that a material's extension is directly proportional to the applied force (load), while it behaves elastically.
What equation represents Hooke's law?
$F = k x$
where F is force (N), k is the spring constant (N m^-1) and x is the extension (m)
What shape is the force-extension graph of a material obeying Hooke's law?
A straight line through the origin
Define the spring constant.
The spring constant, k, is the force per unit extension up to the limit of proportionality; its SI unit is N m^-1.
How can the spring constant be found from a force-extension graph?
The spring constant, k, is the gradient of the linear part of a force-extension graph.
A stiffer spring has a .......... value of spring constant.
A stiffer spring has a larger value of spring constant.
True or False?
The gradient of a length-extension graph, with load plotted on the x-axis, is always equal to the spring constant, k.
False.
If load is on the x-axis and length is on the y-axis, the gradient equals $\frac{1}{k}$ , not k.
Define tensile stress.
$σ = \frac{F}{A}$
The applied force per unit cross-sectional area of a material, measured in Pa.
Define strain.
$ϵ = \frac{x}{L}$
The extension per unit original length; strain is dimensionless.
Define ultimate tensile stress.
The maximum force per original cross-sectional area a wire can support before it breaks.
What equation defines the Young modulus?
$E = \frac{σ}{ϵ} = \frac{F L}{A x}$
measured in Pa
What does the gradient of a stress-strain graph represent?
The Young modulus of the material.
Why is a wire's diameter measured at several points along its length in the Young modulus experiment?
To reduce uncertainty in the cross-sectional area, by calculating an average diameter.
In the Young modulus experiment, the independent variable is the .......... and the dependent variable is the extension.
In the Young modulus experiment, the independent variable is the load and the dependent variable is the extension.
True or False?
Strain has the same units as stress, pascals (Pa).
False.
Strain is a ratio of two lengths, so it is dimensionless and has no units; stress is measured in Pa.

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