Fluids Unit Test Review (Answers)

  1. The three states of matter are solid, liquid and gas.
  2. The two states of matter that are fluids are liquid and gas.
  3. Fluids are different from solids because they flow and they take the shape of their containers.
  4. Flow rate is the amount of fluid that flows in a measured amount of time.
  5. The particle theory states that

All matter is composed of particles

Particles are in constant motion

There are forces of attraction among particles

  1. Solids cannot flow because their particles are strongly attracted.
  2. Laminar flow is smooth flow in nearly straight lines. Turbulent flow is rough, choppy flow.
  3. An aerodynamic shape is curved so that fluids flow smoothly over it.
  4. Drag is the frictional force that occurs between objects and fluids flowing over them.
  5. Cars are designed to have less drag so that there is less wind noise and better fuel efficiency.
  6. A wind tunnel is a tube with large propellers inside to blow air over objects. Wind tunnels are used to test drag and other effects of wind on airplane wings, cars, and models of bridges and buildings.
  7. Flow rate = volume ÷ time
  8. Flow rate = 5L ÷ 40 minutes = 0.125L
  9. Viscosity is the resistance of a fluid to flowing.
  10. When temperature is increased, fluids flow more easily: they have lower viscosity.
  11. Viscosity is caused by the attractive forces between particles.
  12. Fluid with a low viscosity include air and water.
  13. Fluids with a high viscosity include corn syrup and pudding.
  14. The viscosity of chocolate is controlled by temperature and the amount of fat in it.
  15. Mass is a measure of the amount of matter. Weight is the measure of the force of gravity (the pull) on the matter.
  16. Volume is the amount of space a solid occupies. Capacity is the amount of space inside a container.
  17. A meniscus is the curved surface of a liquid in a tube.
  18. Volume can be measured using ml, L, cm3 or m3.
  19. The volume of a rectangular solid: volume = length x width x height
  20. Volume = 4.5 x 10 x 6 = 270 cm3
  21. You can measure the volume of a lump of clay by partly filling a graduated cylinder with water then placing the lump in the cylinder. The change in volume is the volume of the clay.
  22. The particles of a solid are tightly packed together. Liquids have a little space in between the particles and gases have a lot of space between the particles.
  23. 10% of an iceberg shows above water.
  24. The density of water is 1g/ cm3
  25. If you compare the densities of substances, you can identify which will float and which will sink. An object will float if its density is less than the fluid around it.
  26. When MOST solids melt, their density decreases.
  27. volume= 11.1 – 5 = 6.1 mL.

Density = mass/volume = 58g/6.1 mL = 9.5 g/ cm3

  1. Mass = 17.3 – 5.2 = 12.1 g Density = 12.1g / 10 mL = 1.21 g/mL
  2. Density = 1048g/270 cm3 =3.88 g/cm3
  3. a) 7.2 mL b) 109 mL c) 25 mL
  4. The buoyant force on an object immersed in a fluid is equal to the weight of the fluid displaced by the object.
  5. The buoyancy of an object can be increased (float better) by reducing its mass or increasing its volume. (Volume can be increased by heating gases)
  6. Ships and balloons need ballast to control their buoyancy and remain stable.