AP Physics 1 Set 9

fluids

substances that can flow. Refers to both liquids and gases

pressure

if we place an object in a fluid the fluid, the fluid exerts a contact force on the object. How that force is distributed over any small area of the object’s surface

pascal

force is measured in newtons (N) and area is expressed in square meters (m²), the SI unit for pressure is the newton per square meters. This unit has its own nam (Pa). SI unit of pressure: 1 pascal = 1 Pa = 1 N/m²

atmosphere

another common unit for pressure is this (atm). At sea level, this pressure, P atm, is about 100,000 Pa (1 atm)

hydrostatic gauge pressure

the pressure only from the fluid the object is currently submerged in, ignoring the pressure from the surrounding atmosphere

hydrostatic pressure

when liquid is at rest

buoyant force (buoyancy)

the result of the difference in pressure on an object that is inside a fluid. It points opposite of the force creating the pressure (usually gravity)

archimedes’ principle

states the strength of the bouyant force on an object is equal to the weight of the fluid displaced by the object

volume flow rate

f; is the volume of fluid that passes a particular point per unit time

continuity equation

when the density of the fluid is constant: A1v1 = A2v2

bernoulli’s equation

the statement of conservation of energy for ideal fluid flow

viscosity

the force of cohesion between molecules in a fluid; think of it as internal friction for fluids. For example, maple syrup is sticky and has a greater (blank) than water

streamline (or laminar) flow

occurs when each part of the fluid flows smoothly in a line without crossing

turbulent flow

the opposite of streamline flow and is characterized by rapidly swirling whirlpools; such chaotic flow is unpredictable

bernoulli (or venturi) effect

states that at comparable heights, the pressure is lower where the flow speed is greater