Forces in Fluids

Volume – the amount of space taken up by matter.◦ Gasses expand to fill their container.

Temperature- the measure of the motion of the particles◦ Faster moving particles have a higher

temperature. Pressure – when gas particles are moving

they collide with the sides of their container. The pressure measures the force of those collisions.

Measuring Gases

Boyle’s Law – As volume of the gas decreases, the pressure increases.◦ Example: When you decrease the volume in a

piston the pressure inside the piston increases

Gas Laws

Charles Law – As the temperature of the gas increases the volume will increase.

Example: When you heat up a balloon it will expand.

Gas Laws

States that when a force is applied to a confined fluid, the change in pressure is transmitted equally to all parts of the fluid.

Hydraulic devices use Pascal’s principle.◦ You apply a small force over a small area and

because the pressure is transmitted equally it can produce a larger force over a bigger area.

Pascal’s Principle

Pascal’s PrinciplePascal’s Principle: You exert a pressure on the left piston and it translates into a larger force on the right piston.

Buoyant force – the upward push of a fluid on an object.◦ Example: when you are in water, gravity is pulling

you down but you feel lighter because the buoyant force of the water is pushing up on you.

Forces in Fluids

◦ Archimedes principle says that the buoyant force equals the weight of the water displaced by the object. So if you displace 50 pounds of water, the buoyant force equals 50 pounds.

◦ Objects float when the buoyant force is the same as the weight of the object. So if you displace 50 pounds of water and you weigh 50 pounds you will float.

Forces in Fluids

Forces in Fluids

Bernoulli’s principle says that the faster a fluid moves the less pressure it has.◦ Example: A shower curtain will move inward

when you first turn on the water. This is because the fast flowing water creates an area of low pressure inside the shower.

Forces in Fluids

Forces in Fluids