5. Particle movement in matter
What happens when a particle moves in another matter?

6. Approach:
Solids
Deformations
Stress
Strain
Elasticity
Fluids
Pressure

7. Matter Anything that occupies space and has mass.
Volume
Mass
Density
Exhibits gravitational attraction
Has inertia

8. States/Phases of Matter
Solid
Liquid
Gas
Plasma
Supersolids
Superfluids

9. Some properties of solids
Elasticity
Malleability
Ductility
Plasticity
Strength
Hardness
Flexibility

10. Elasticity vs. Plasticity
Elastic and plastic materials are both deformed when subjected to force
Difference:
Elastic: material returns to its original dimension when force is removed
Plastic: deformation is permanent
Elastic materials may exhibit plasticity.
When and how?

11. Malleability vs. Ductility
Both are determined by the crystal lattice of the metal, and the strength of the bond between molecules of the metal
Copper is malleable and ductile. Aluminum is malleable but not as ductile as copper.

12. Hardness vs. Strength
In the general use, they are the same; the ability o a material to resist deformation
Concrete is hard but it may not be as strong as metal.
Hardness … deformation due to compression
Strength … deformation due to tension

13. Hooke’s Law Also known as Law of Elasticity Robert Hooke
For relatively small deformations, the magnitude of deformation is directly proportional to the deforming force.

14. Limitations Conditions that fall under Hooke’s Law
Relatively small deformation
Deformation is within the elastic limit
The material returns to its original dimension when the force is removed

15. Illustration for Hooke’s Law
Greater deformation requires greater force.
The ratio of these too defines the elasticity of the material

16. Deformation Quantified
Deformation will now be called strain in our analysis, and the deforming force will be represented as stress.
Note: However do not think that stress is a force.

17. Young’s Modulus of Elasticity
Also called ELASTICITY OF LENGTH
Describes the stiffness of materials; resistance to compression and tension in one axis
High value of Y means high resistance

18. Shear Modulus of Elasticity
Also called elasticity of shape or modulus of rigidity
High value of S means high rigidity

19. Bulk Modulus of Elasticity
Also called elasticity of volume
Its reciprocal is called compressibility
Higher value of K means the material is harder to compress.

20. Typical Values for Elastic Moduli
Substance
Young’s Modulus
(GPa)
Shear Modulus
Bulk Modulus
Aluminum
70.0
25.0
Bone
18.0
80.0 -
Brass
91.0
35.0
61.0
Copper
110
42.0
140
Steel
200
84.0
160
Quartz
56.0
26.0
27.0

21. Exercises
A wire 2.50 m long has a cross – sectional area of 2.00x10-3 cm2. When stretched by a force of 80.0 N it elongates by 5.00x10-2 cm. Determine
the tensile stress
the tensile strain
the Young’s Modulus of this kind of wire.
If this material has twice the cross-sectional area with the same length, what must be the magnitude of deformation when subjected to the same force?

22. Exercises
A certain metal can withstand a maximum shear stress of 8.65 GPa. What magnitude of force is required to puncture a hole of 3.00 cm radius on a metal bar that is 4.00 cm thick?

23. Exercises
How much is the decrease in the volume of 5.00 cubic centimeter of aluminum when submerged in the sea at a depth where the pressure is 2.35 MPa?

24. Seatwork
A vertical steel beam in a building supports a load of 6.00x104 N. If the length of the beam is 4.00 m and its cross-sectional area is 8.00x10-3 m2, find the distance it is compressed along its length.

25. Seatwork
A solid sphere of volume m3 is dropped in the ocean to a depth of about 2,000 m where the pressure increases by 2.00x107 Pa. Lead has a bulk modulus of 7.70 GPa. What is the change in the volume of the sphere?

26. Seatwork
What magnitude of force is required to puncture a square hole, 3.00 cm on each side, on a steel bar of 5.00 cm thickness? The maximum stress that steel can withstand is approximately 85.0 GPa

27. Assignment Prepare for seatwork on Elastic Moduli
Answer the following questions in your LNB.
What is the atmospheric pressure at sea level (standard atmospheric pressure)?
Differentiate gauge pressure and absolute pressure.
State Pascal’s Principle on hydrostatic pressure.
Illustrate and explain Pascal’s Principle using Pascal’s vases and hydraulic press.