CHAPTER 7. MECHANICAL PROPERTIES OF MATTER 7.4
- Materials have the following mechanical properties to a greater or lesser degree:
strength, hardness, ductility, malleability, brittleness, stiffness. - Materials can be weakened by have the following problems in their crystal lattice:
vacancies, dislocations,impurities, difference ingrain size. - Materials can have their mechanical properties improved by one or more of the
following processes: cold working, annealing, adding impurities, tempering, sin-
tering.
Chapter 7 End of Chapter Exercises
- State Hooke’s Law inwords.
- What do we mean by the following terms with respect to Hooke’s
Law?
(a) elastic limit
(b) limit of proportionality - A spring is extendedby 18 cm by a force of 90 N. Calculate the spring
constant for this spring. - A spring of length 8cm stretches to 14 cm when a load of 0,8 N is
applied to it.
(a) Calculate the springconstant for the spring.
(b) Determine the extension of the spring if a load of 0,7 N is applied
to it. - A spring has a springconstant of− 150 N.m−^1. By how much will it
stretch if a load of 80 Nis applied to it? - What do we mean bythe following terms when speaking about prop-
erties of materials?
(a) hardness
(b) toughness
(c) ductility
(d) malleability
(e) stiffness
(f) strength - What is Young’s modulus?
- In what different ways can we improve the material properties of sub-
stances? - What is a metal alloy?
- What do we call analloy of:
(a) iron and carbon
(b) copper and zinc