**Materials and Fluids**

designed by Dr T. Marlow

## Specification:18 understand and use the terms
density, laminar flow, streamline flow, terminal velocity, turbulent , flow upthrust and viscous drag, for example, in transport design or in manufacturing19 recall, and use primary or secondary data to show that the rate of flow of a fluid is related to its viscosity 20 recognise and use the expression for Stokes’s Law, F = 6πηrv and upthrust = weight of fluid displaced.21 investigate, using primary or secondary data, and recall that the viscosities of most fluids change with temperature. Explain the importance of this for industrial applications 22 obtain and draw force–extension, force–compression, and tensile/compressive stress-strain graphs. Identify the limit of proportionality, elastic limit and yield pointObtain graphs for, example, copper wire, nylon and rubber investigate and use Hooke’s law, F = kΔx, and know that it applies only to some materials24 explain the meaning and use of, and calculate tensile/compressive stress, tensile/ compressive strain, strength, breaking stress, stiffness and Young Modulus. Obtain the Young modulus for a material. Investigations could include, for example, copper and rubber25 investigate elastic and plastic deformation of a material and distinguish between them 26 explore and explain what is meant by the terms brittle, ductile, hard, malleable, stiff and tough. Use these terms, give examples of materials exhibiting such properties and explain how these properties are used in a variety of applications, for example, safety clothing, foodstuffs27 calculate the elastic strain energy Eel in a deformed material sample, using the expression Eel = ½ Fx, and from the area under its force/extension graph |