Fluid Pressure

Question 1

what is pressure

Answer 1

the force (exerted) per unit area

Question 2

what is the formula for calculating pressure

Answer 2

• pressure = force normal to the surface / area of that surface
• p = f / a

Question 3

what are the units for pressure, force and area in the formula for calculating pressure

Answer 3

• pressure in pascals = Pa OR N/m^2
• force normal to the surface = N
• area of that surface = m^2

Question 4

what do gases and liquids both have in common

Answer 4

• their particles are free to move and flow

- so they are both fluids

Question 5

what is fluid pressure

Answer 5

pressure caused by the collision of gas or liquid particles in a given surface

Question 6

what does fluid pressure always exert

Answer 6

• a force at right angles to any surface in contact with the fluid
• the right angle is the normal

Question 7

what happens to the pressure exerted on the area of the surface it is colliding with increases

Answer 7

the pressure decreases

Question 8

what are the three factors that the pressure exerted by a fluid is dependent on

Answer 8

• the area that the force is being exerted on
• the properties of the fluid
• and the surrounding atmospheric pressure

Question 9

what is density

Answer 9

• the compactness of an object

- or how close together the particles that make the object are

Question 10

what is the density of a liquid like

Answer 10

• the density is uniform (the same everywhere)

- and doesnt vary with a change in the size or shape of it

Question 11

what are the differences between how the density of a gas and a liquid generally behaves

Answer 11

• the density of a liquid remains constant no matter its shape or size
• whereas the density of a gas can change depending on some factors

Question 12

assuming that the mass of the particles of two fluids are the same, how would one fluid be denser than the other

Answer 12

the denser fluid would have more particles in a given area than the less dense fluid

Question 13

what is the effect of a fluid being denser than another one in terms of pressure

Answer 13

• it meas that there are more particles that are able to collide with the surface of the area they are in
• which leads to an increase in pressure at a given depth in the denser fluid

Question 14

what changes as the depth of a fluid increases

Answer 14

• the number of particles above it at that point changes

- specifically, it increases

Question 15

why does fluid pressure increase with depth

Answer 15

• the deeper you go down a fluid or the higher the depth of the fluid is
• the more particles that will be above it at that point
• the weight of these particles above that point adds to the pressure felt at that point of depth
• and with an increased force with the area of the surface remaining the same, according to p = F / A
• the fluid pressure would increase

Question 16

what equation do you use to calculate the pressure due to the column of liquid above a certain depth

Answer 16

• pressure due to a column of liquid = height of the column (the depth) x density of the liquid x gravitational field strength
• P = h * p (greek letter for ‘rho’) * g

Question 17

what are the units for the pressure due to a column of liquid, the height of the column, the density of the liquid and the gravitational field strength

Answer 17

• pressure due to a column of liquid = Pa
• height of the column = m
• density of the liquid = kg/cm^3
• gravitational field strength = N/kg