BRAINCAKEFluids
Revision notes for Fluids in Edexcel Physics (8PH0). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.
- FluidsA fluid is defined as any substance that can flow.
- Densitydensity ρ = mass (kg) volume (m3) The units of density are kg m-3 Density is mass per unit volume.
- UpthrustUpthrust is the upwards force felt by a submerged object caused by fluid pressure.
- Floating and SinkingAn object will sink if the upthrust is less than the weight.
- HydrometerA hydrometer is an instrument used to measure density.
- Laminar FlowLaminar flow or streamline flow occurs at relatively low speeds.
- Turbulent FlowWith turbulent flow the fluid velocity at a particular place changes over time.
- StreamliningThe lines of laminar flow are called streamlines.
- ViscosityThe frictional force in fluids caused by movement through the fluid is due to viscosity.
- Investigating Flow RatesThe rate of flow of a fluid through a pipe is inversely proportional to the viscosity of the fluid.
- Investigating Viscosity Changes with TemperatureThe viscosity can be calculated by allowing small spherical objects of known weight to fall through a fluid until they reach terminal velocity.
- Viscous DragViscous drag is the frictional force between a solid and a fluid.
- Stokes' LawStokes' law is the equation for the viscous drag F on a small sphere at low speeds.
- Terminal VelocityFor a small sphere of radius r Volume V = (4/3)πr3 density ρs falling through a fluid of density ρw and viscosity ηw weight of sphere = mg = ρsV g…
- Investigating Terminal VelocityDrop steel ball in viscous fluid and measure terminal velocity by timing how long the ball takes to move a fixed distance and recording the velocity…