Hooke’s law 1.Hooke’s law describes how the strain on an elastic material is related to the stress placed on the material. It is a principle of physics that states that the force needed to extend or compress a spring. The theory of elasticity generalizes Hooke’s law to say that the strain of an elastic object or material is the same to the stress applied to it. The purpose of this lab experiment is to study the changes of springs in static and dynamic situations and how they act.
Too will look for the spring’s constant, for an individual spring using both Hooke’s Law and the properties of an oscillating spring system. It is also possible to study the effects (if any) that amplitude has on the period of a body.Young’s modulus is a measure of stiffness; this is a mechanical property that measures how stiff a solid material is, and also is how much elasticity an object or substance has.
This tells us how likely a material is to be deformed when a force is applied to it and whether not or not it will return to the original shape when the force is removed. The elastic modulus of an object is defined as the slope of its stress-strain curve.2.Concrete: The property of a material to withstand against the action of atmospheric and other factors is known as durability of material. If the material is more durable, it will last long and well so Maintenance cost of material is dependent of durability so you don’t have to renew something often. Heat tolerance is high so it can with stand natural temperatures. Density varies depending on the mix; high density concrete is about 2.5g/cm3 low density concrete is 0.4 to 2.0g/cm3.Brick: bricks are durable, low-maintenance and attractive building material’s made from clay, sometimes with other chemicals added during manufacture. The clay is pressed into moulds and fired at temperatures up to 1000 degrees. Most bricks are rectangular; the most common size is 215 x 102 x 65 mm. density varies but generally around 1.85g/cm3, compression strength ranges from 4 to 180N/mm2.water content reduces compression strength and thermal resistance. Plastics: produced as a by-product of the oil industry, plastics are very lightweight and do not absorb water, therefore they are not affected by frost. Plastics are used for pipes, damp-proof courses, window frames, floor coverings, fillers and sealants, plugs, sockets, thermal insulation. They are used because they are good electrical insulators. There are two types of plastics- thermoplastic, becomes soft when heated and hardens on cooling and thermosetting, does not soft when heated but can char with excessive heat.3.Different types of stressesTensile stress: There exists a state of stress between the fibers on one side of plane x-x and those on the other. The stress is evenly spread across the cross section sand set up along the whole length, just as in a chain resisting forces are set up by every linkCompressive stress: Compressive stress is similar to tension stress but the forces go towards each other putting the bar in compression. Here the cross section is resisting the tendency of the fibres to be crushed Bending stress: Bending stress is a type of stress seen when loads are applied perpendicularly to an object, forcing it to deflect under the load. Deflection: The deformation of a beam is usually expressed in terms of its deflection from its original unloaded position, this deflection depends on its length, shape, the material, where the force is applied, and how the beam is supported.4. A force is any push or pull, Forces act on all structures whether the structure is small or large, it must be designed and built to withstand the forces it will face. Structures should be designed to withstand the forces that can act on them, these forces could be external (wind) or anything natural. Gravity also plays its part is the natural force of attraction between two objects. Gravity constantly pulls structures toward Earth’s centre.Every structure needs to support a load. The total load is the sum of the static and dynamic loads. The static load is the effect of gravity on a structure. The dynamic load is the forces that move or change while acting on the structure.When engineers design structures such as bridges and large buildings, they consider all the forces that could affect it over its lifespan. For example, a bridge in winter has to supports snow as well as the cars and trucks. Buildings in areas with a lot of earthquakes must be able to withstand the shaking without losing their windows or falling down.Temperature change1) Identify and describe the 5 key properties of construction materials which are affected by temperature change. For a material to be considered as good suitable building material, it should have the needed engineering properties suitable for construction works. These properties of building materials are responsible for its quality and capacity and help to decide applications of this material. Physical propertiesMechanical propertiesChemical propertiesElectrical propertiesMagnetic propertiesThermal propertiesPhysical proprieties: These are the properties needed to estimate the quality and condition of any material without any external force being used. The physical properties of engineering materials are as follows. Bulk density, Porosity, Durability, Density, Density index, Specific gravity, Fire resistance, Frost resistance, Weathering resistance, palling resistance, Water absorption, Water permeability, Hygroscopicity, Coefficient of softening, Refractoriness. None of these would be affected by temperature change.Mechanical properties: Mechanical properties of the materials are found out by applying external forces on them. These are important properties which are responsible for use of a material in its job. The mechanical properties are: Strength, Hardness, Elasticity, Plasticity, Brittleness, Fatigue, impact strength, Abrasion resistance, Creep.Chemical properties: The ability of construction materials to resist the effects by chemicals like acids, salts and alkalis is known as chemical resistance. The properties of materials against the chemical actions or chemical combinations are termed as chemical properties, they are: Chemical resistance, Corrosion resistance.Electrical properties: this is a property of a material that shows how strongly that material opposes the flow of an electric current. The properties of a material to conduct or to resist electricity through them are electrical properties of material. For example, wood have great electric resistance and stainless steel is a good conductor of electricity. This would weather proof if made and fitted right depending what it is.Magnetic properties: The magnetic properties of materials like permeability, hysteresis etc. is required in the case of generators etc. iron is magnetic material and aluminium is non-magnetic material.Thermal properties: Thermal capacity is the property of a material to absorb heat and it is required to be proper ventilation. It shows the thermal stability of walls. It is expressed in J/N oC and it is calculated by below formula. The properties are: Thermal capacity, Thermal conductivity, Thermal resistivity, Specific heat.2) Identify and explain the 3 possible states of matter.The three states are solid, liquid, gas. 3) Explain the term evaporationEvaporation is the term used for when water is boiled and turns into a gas and is released.4) Identify and explain expansion and contraction and how two different construction materials can beA contraction is the act of decreasing the size of something or shortening it or it can be the process of becoming smaller or compressed. The two most well-known uses of contraction involve muscles and words but are also used for materials used in construction.Expansion is the increase in the volume of a substance while its mass remains the same. Expansion is usually due to heating, when substances are heated the molecular bonds between their particles is weakened, and the particles move faster, causing the substance to expand.Timber can be affected by water as it can cause rooting will make the wood lose its strength and become weak leading it to snap and bend. Timber can also be affected by ice as when it freezes the ice makes the timber expand and lose strength and be out of place.