Fluids

  • Properties of matter:

    • Solid

      • Fixed shape and volume

      • Particles locked in rigid structure

      • Almost no compressibility

      • Little space between particles

      • Almost no ability to flow

    • Liquid

      • Assumes the shape of the container it occupies

      • Particles can move/slide past each other

      • Not easily compressed

      • Little space between particles

      • Moderate ability to flow

    • Gas

      • Assumes the shape and volume of the container it occupies

      • Particles move past each other and bump into the sides of the container

      • Compressible

      • A lot of space between particles

      • Flows easily

understanding that both liquids and gasses are fluids

The ice cube has a certain mass and shape, and neither of these quantities depends on the size or shape of the glass.If the ice melts, the water flows to take the shape of its container and forms a definite, flat, upper surface.If you boiled the water, the resulting gas (water vapor) would flow and expand to fill the room but would not have any definite surface. oth liquids and gases are fluids, which are materials that flow and have no definite shape of their own.

Fluids

Fluids are the substances that flow easily because of increased intermolecular spaces and do not have fixed shape. Liquids and gases are considered as fluids.

Density

  • is the measurement of how tightly a material is packed together. It is defined as the mass per unit volume Density Symbol: D or ρ Density

  • Formula: ρ = m/V,

  • where ρ is the density, m is the mass of the object and V is the volume of the object

Pressure

  • is The force applied perpendicular to the surface of an object per unit area over which that force is distributed

  • The basic formula for pressure is P=F/A (Force per unit area)

Buoyancy

  • the ability or tendency of something to float in water or other fluid.

  • Ex. A boat or a ship floating in the water and the floating of cork in water

how are pressure and force related to each other

  • (P) is the perpendicular component of a force on a surface divided by the area of the surface.

  • Pressure is a scalar quantity.

  • In the SI system, the unit of pressure is the pascal (Pa), which is 1 N/m^2

  • Since pressure is force exerted over a surface, anything that exerts pressure is capable of producing change and doing work.

  • An ideal gas is a gas whose particles take up no space and have no intermolecular attractive forces.

  • The pressure exerted by a gas can be understood by applying the kinetic-molecular theory of gases, which explains the properties of an ideal gas.

  • According to this theory, the particles in a gas are in random motion at high speed and undergoing elastic collisions with each other.

  • When a gas particle hits a container’s surface, it rebounds, which changes its momentum. The impulses exerted by many of these collisions result in gas pressure on the surface.

  • Pressure = force over area

Example answer

Problem

How does the average pressure of an elephant standing on the ground compare to that exerted by a person standing on the ground? The person weighs 640 N. Each shoe has an area of about 0.016 m^2 in contact with the floor. The elephant weighs 4.13×10^4 N and has four feet, each with an area of about 0.14 m^2 in contact with the ground.