AP Physics U8

Solids and liquids have constant volume/density but…

gas doesn’t

Units of density

kg/m³

Units of pressure

N/m² (Pa)

Atm pressure

1.0 × 10^5 Pa

Water’s density

1000 kg/m³

For buoyant force formula p and v stand for…

density of fluid and volume of fluid displaced

For floating objects…

Fb = mg or pvg = pvg

Also for floating objects…

p cube/ p water (fluid) = v fluid displaced/ v cube

ideal fluid

water in incompressible, volume liquid system conserved, constant volume of water passing per second

Fluid flow rate Q =

volume/time (m³/s)

When Q is constant

A1v1 = A2v2

one pipe opening to two pipe opening:

half A1V1 for both openings

There is more pressure when vertical height…

goes lower

Speed is inversely related to …

pressure

Torricelli’s theorum (hole in bucket)

pgy = 1/2pv2²

Velocity of t’s theorem

v2 = sqr(2gdeltay) delta y is depth of hole

Fluids go from high to

low pressure

When object is floating, heavier objects have ___ buoyant forces

larger

Weight of fluid displaced =

weight of object

Objects made out of the same material have the same…

density!

Thick lids will exert additional ____ on a sealed container filled with liquid.

pressure

If there is a hole in a sealed container of water, how much liquid would leave the hole and why?

None! The pressure at the hole is larger that the pressure at the top of the liquid since it also has atm pressure. Liquid moves from high to low pressure.

Use what eq for pressure differences

Bernoulis!