week 3

Question 1

what is pressure

Answer 1

the measure of how concentrated a force is

Question 2

formula for pressure

Answer 2

force over area

Question 3

what is hydrostatic pressure

Answer 3

the pressure present within a fluid when it is at rest

Question 4

how does hydrostatic act (directions)

Answer 4

acts equally in all directions. it also acts at any right angle to any surface in contact with the fluid

Question 5

what is absolute pressure

Answer 5

this is the pressure measured relative to a vacuum

Question 6

what is gage pressure

Answer 6

this is the pressure measured relative to the ambient pressure (which is usually the atmosphere pressure)

Question 7

what is a manometer

Answer 7

this is a device that measures pressure differences using fluid columns that are at rest in vertical or inclined tubed

Question 8

what is the rule when working out pressure for a U -tube manometer

Answer 8

add gammer height (yg) when going up
minus (yg) when going down
vertical has no change

Question 9

what are most preesure measuring devices calibrated to? and what does it indicate

Answer 9

0 and therefore indicates gage pressure

Question 10

what is preesure below the atmosphere called?

Answer 10

vacuum pressure

Question 11

what is the pressure at any point?

Answer 11

the same in all directions, it has a magnitude but not a direction

Question 12

what happens to pressure when you go deeper

Answer 12

pressure increases with depth as more fluid rests in the object

Question 13

what is the pressure at 2 points at the same elevation in a continuous fluid

Answer 13

the pressure is the same

Question 14

how can pressure be determined

Answer 14

by andding and subtracting pgh terms

Question 15

what are manometers used for

Answer 15

to measure drops across valves, pipes, heat exchangers…

Question 16

how do you work out pressure drop p1-p2

Answer 16

by starting at point 1 and adding or subtracting pgh terms until you reach pressure 2

Question 17

what device is used to measure atmospheric pressure

Answer 17

by a device called barometer, thus, atmospheric pressure is referred to barometric pressure

Question 18

what effects pressure during elevation

Answer 18

aircraft preformance, engine perfornace and cooking (other stuff too)

Question 19

what is buoyancy

Answer 19

upward force by fluid pressure

Question 20

why does buoyancy happen

Answer 20

this is due to the fluid displaced by a body

Question 21

what is the archimedes principal

Answer 21

this is the boutant force acting on a body immered in fluid, which is equal to the weight of the fluid

Question 22

what is the buoyancy force equal to?

Answer 22

this is equal to the displaced volume

Question 23

possible 3 scenarios for buoyancy

Answer 23

p body < pfluid: Floating body

2. p body = p fluid: Neutrally buoyant
3. p body > p fluid: Sinking body

Question 24

what is galilean thermometer

Answer 24

this is the glass cylinder which contains weights. these adapt in height depending on their density if its equal to the surrounding liquid.

Question 25

what property will cause the weights to differ in the galilean thermometer

Answer 25

temperature can cause the weights to change in height because the glass will expand in heat thus making the liquid less dense

Question 26

if a object is less dense that an liquid, will it sink?

Answer 26

no, only if an object is more dense than liquid it will sink

Question 27

what is pascal’s law

Answer 27

when there is an increase in pressure in a confined fluid, there is an equal increase at every other point in the container

Question 28

what is Bernoulli’s principle

Answer 28

an increase in the speed of a fluid occurs simultaneously with a decrease in pressure or a decrease in the fluids potential energy