4.1Fluid Density And Upthrust Flashcards
What is a fluid ?
A fluid is any substance that can flwo.
Normally a gas or liquid
or a solid made from time particles that act as fluids such as sand.
How do you calculate the mass of fluid displaced?
The mass of a fluid displaced is equal to the volume x desnsity
m = V x ρ
What is Upthrust?
Upthrust is the upwards force caused by the object displacing the fluid.
As objects sink deeper into the fluid the volume of fluid displaced increases so upthrust will increase.
What is the defention of density?
Mass per unit volume.
What is Archimedes Principle?
Archimedes Principle states that
upthrust on an object is equal to the weigh of the fluid displaced.
u = w
w = m g ρ = m / v m = v x ρ
u = ρ v g
What is a hydrometer?
A hydrometer is an intrument used to determine the desnity of a fluid.
A hydrometer has a constant weight so it floats in fluids of less density/
What is Laminar / Streamline flow?
This is where a fluid moves with uniform lines where velocity is constant overtime.
What is turbulent flow?
This is where a fluid velocity in a particular place changes over time, often in an unpredictable manner. eddies occur.
What is viscosity?
How resistant a fluid is to flowing.
What is the co efficient of velocity?
A numerical value given to a fluid to indicate how much it resitns flow
η (eta)
What is terminal Velcoity?
This is the velocity of a falling object when its weight is balanced by the sum of upthrust acting on it.
Applicable to objects falling under gravity
with a constant weight.
When can stokes law be applied ?
To object moving at low speeds , small speherical objects with laminar flow.
What happens to viscosity when temperature is increased and decreased?
when temperature is high viscoity is low and vice versa.
