Physics - Fluids and Solid 3

The force applied to an object divided by the area over which the force is applied.

Stress = F/A

Note that to distinguish from pressure, we use the unit N/m² instead of Pa.

We use the unit N/m² instead of Pa.

Fractional change in object's shape. Strain is a ratio of change, so it has no units.


Strain = delta dimension / original dimension.

• Since stress and strain are proportional to each other.
• The proportionality is given by modulus of elasticity.

Modulus of elasticity = stress / strain

Proportional to.

Yield point.

The stress is less than yield point.

When the stress exceeds the yield point.

(E) Young's modulus: Tensile stresss

(G) Shear modulus: Shear stress

(B) Bulk modulus: compression and expansion.


All moduli work in both direction, e.g. Young's modulus works for tensile compressive force and tensile stretching forces.

Remember that it's not the net force be used here because it might get 0 net force, instead, it is one of the magnitude of the force is used.

F/A = 1/E x ( delta h / h_{o )}

F/A = 1/G x (delta x / h_o )

F/A = 1/B x [delta p / (delta V / V_o )]

Expands.

When their molecule absorbs energy their vibration increase, thus they need more room for vibration.