Physics (Liquids)

posted by .

I have a question about fluids ok...

I've been told that
Pressure = (density of fluid) (gravity) (height)

ok that's great in all but I don't see how it works...

Pressure = (Force perinduclar to area force is acting on)/(Area force is acting on)

ok this great and all but leads me to several questions ok the force perpendicular to area it acts on is gravity

1.) WHY NOT THE BOUYANCY FORCE?

assuming that the force is gravity then

Force of gravity = (mass)(gravity)

for objects near surface of planet

so plug into our pressure equation

Pressure = ( (mass of object)(gravity) )/(Area the force is acting on)

my book then goes on to say

density of an object = (mass of object)/(volume of object)
ok rearaning for mass

(density of an object)(volume of object) = objects mass

plug and chug into our Pressure equation...

Pressure = ( (density of an object)(volume of object)(gravity) )/(Area the force of gravity is acting on)

Volume of uniform solid = (area of bottom)(height of object)

pluging into our Pressure equation

Pressure = ( (density of mass)(gravity)(area force of gravity is acting on)(height of object) )/(area force of gravity is acting on)

area cancels out

Pressure = (density of mass)(gravity)(height of ojbect)

ok I followed this derivation step by step but it's wrong WHY???

my book gives me this equation

Pressure = (density of fluid object is in)(gravity) (how far submerged the object is in the fluid, the depth i believe the term is like how far under the surface the object is)

this does not match my equation

2.) The density of the object changed to the denisty of the fluid it's in

3.) The height of the object changed to how far under the surface the object is

4.) How do I use this equation when it's not a uniformed block? I couldn't right? Like if it were a person...

THANK YOU
Please I need to understand this... I don't see how such a simple derivation just changes variables around and such...

  • Physics (Liquids) -

    I HAVE FIGURED IT OUT

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Physics

    Europa, a satellite of Jupiter, appears to have an ocean beneath its icy surface. Proposals have been made to send a robotic submarine to Europa to see if there might be life there. There is no atmosphere on Europa, and we shall assume …
  2. physics

    why does an ideal fluid move faster through a pipe with decreasing diameter?
  3. fluid mechanics

    I have got differential pressure from an inclined manometer to be 2.8kPa and density of the fluid is 784kg/m^3. I need to calculate the manometer datum height. how do i do tht?
  4. fluid mechanics

    I have got differential pressure from an inclined manometer to be 2.8kPa and density of the fluid is 784kg/m^3. I need to calculate the manometer datum height. how do i do tht?
  5. fluid mechanics

    I have got differential pressure from an inclined manometer to be 2.8kPa and density of the fluid is 784kg/m^3. I need to calculate the manometer datum height. how do i do tht?
  6. Equation Help

    In our text book the following equation is given: P=(pm - p)g * R where P is the pressure drop R is the manometer reading pm is the density of the manometer fluid p is the density of the process fluid in the pipe g is the acceleration …
  7. Chemistry

    n our text book the following equation is given: P=(pm - p)g * R where P is the pressure drop R is the manometer reading pm is the density of the manometer fluid p is the density of the process fluid in the pipe g is the acceleration …
  8. Physics

    Assuming the fluid has a density of 1.00 (g/cm^) at what height h should the bottle be placed so the liquid pressure is 38mm-Hg ?
  9. Physics

    When a person is given intravenous fluid, the bag containing the fluid is typically held about 1.2 m above the person's body. If the pressure in this fluid is just barely able to push the fluid into the person, what is the pressure …
  10. Physics

    1. What is the kinetic energy of a 0.50 g insect traveling in a straight line at 5.0m/s?

More Similar Questions