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6. which of these is a catergories/mechanisms of injury?
- Fast pace implements
- Whiplash
- High velocity projectiles
- Angular implements
- Indirect implements
7. Which of these is Not a way in which a material can fail.
- Combustion which is heating
- In tension: which is pulling
- In shear: which is sliding, or the tendency for one part of a solid to slide past another.
- In compression: which is pushing.
8. Most mechanical properties can be determined by carrying out a simple tensile test
9. How can you test the mechanical properties of a material
- A dumbbell shaped sample is gripped at both ends and stretched. The extension (how much it stretches) and the force is continuously monitored
- Heat the material
- Freeze the material and allowing it to cool
- Electronic microscope
10. Stress can be determined as:
- An injury attained during a fast pace environment
- the change in length over the original length
- the force per unit area (N/m2) or Pa
- the amount of heat a material can withstand
11. A Newton is defined as the force which when applied to a mass of 2kg gives it an acceleration of 1m/s2.) 2kg=9.81N
12. Which of the following is incorrect
- Strain is represented in a ratio which is unit length
- Strain is measured in cm/mg
- The stress at failure is known as the strength of the material.
- Strain is the change in length over the original length
13. Which of these is not derived from young modules?
- Stress is Strain
- Strain is propertional to stress
- The correct symbol for the Young
- A steep/high slope and the material is said to be stiff and a low slope and the material is said to be complian
14. The maximum point the curve reaches indicates on the y axis the breaking stress (strength) or on the x axis the extensibility or breaking strain
15. The strength of a material is its ability to resist the application of forces without compressing
16. Which best describes Elasticity?
- If a material is stretched and then, after the force is removed, it returns to its original length it is said to be elastic
- The ability to return to a form after compression
- A string which rebounds after tugging
- Flexibility of molecules
17. This point where the material undergoes plastic deformation is said to be the elastic limit.
18. Which of these are Not a mechanical term
- Inflation
- Yielding point
- Breaking point
- Breaking energy
- Initial modules
19. Work of fracture or toughness is a measure of the energy required to stretch a material. This has units of energy (J) per unit area (m) i.e. J/m
20. Which is true about resilence?
- resilence equates toughness
- material cannot break if melted first
- If a material is stretched and then released the unloading curve is always below the loading curve: some of the energy is lost.
- brittle material has high resilence