ENG1001 Tutorial 2

Stress is...

• an external force

• an internal resistive force

• an axial force

• a radial force

Which of these is not a type of stress?

• Tensile stress

• Shear stress

• Volumetric stress

• Compressive stress

Strain has units of...

• metres, $\mathrm{m}$

• Newtons, $\mathrm{N}$

• Pascals, $\mathrm{Pa}$

• nothing

Stress has units of...

• metres, $\mathrm{m}$

• Newtons, $\mathrm{N}$

• Pascals, $\mathrm{Pa}$

• nothing

Hooke's law is valid for (a)   elastic materials.

Stainless steel has a Young's modulus of 210 GPa. This is equivalent to:

• $210\times10^6$ Pa

• $210\times10^9$ Pa

• $2.1\times10^{11}$ Pa

• $2.1\times10^{12}$ Pa

The equation to find a change in length for a linear-elastic material is given by:

• $\Delta l\ =\ \frac{Fl_0}{EA_0}$

• $\Delta l\ =\ \frac{Al_0}{EF}$

• $\Delta l\ =\ \frac{El_0}{FA_0}$

• $\Delta l\ =\ \frac{EF}{A_0l_0}$

The maximum stress that a material can withstand without breaking is called the (a)   tensile stress.

Dog bone shapes for specimens are used in tensile testing because they are... (select all that apply)

• easy to mount and manufacture

• guarantee that fracture doesn't occur at the ends of the sample

• reduce the chance of slippage whilst testing

• confine deformation in the uniformly-thick centre region

On this diagram, which letter shows the section where the material is undergoing plastic deformation?

• A

• B

• C

• D