Fluids and Pressure

Fluids Remember that both gases and liquids are FLUIDS. ALSO remember that the molecules are constantly moving.

Fluids under Pressure All fluids exert pressure onto something. Pressure is the amount of force exerted on a given surface area. The formula is: P = F/A

Fluids and Pressure Pressure is measure in N/m 2 more commonly known as a Pascal. 1 Pa = 1newton over 1 meter squared

Think About It Which would hurt more? A woman stepping on your toes in sneakers or a woman stepping on your toes in a high heal spike. Why?

Try Some If you apply a 7 N force to an area that is 3 m 2 then how many Pascals do you have? Would the pressure go up or down if I increased the size?

Pascals Principal Pascal stated that a change in pressure at any point in an in closed fluid will transmit that pressure equally to all parts of the fluid. This means that the pressure you apply to the bottom of a tube of tooth paste must be the same pressure felt at the top of the tube of toothpaste.

Pascals Principal Mathematically: P 1 = P 2 Do practice on page 93.

Buoyant Force All fluids exert an upward force = Buoyancy Archimedes principal states: The buoyant force on an object in a fluid is equal to the weight of the fluid that the object displaces.

Buoyant Force Another way to determine if an object will float is too determine it’s density. Remember that Density = mass/volume. If an object is less dense than the liquid it is in then it will float.

Think About It How do large ships made of dense material stay afloat?