CHAPTER 11

Question 1

what is pressure

Answer 1

the result of when objects wont exert force on eachother

Question 2

how to increase pressure 2

Answer 2

decrease sa

increase force

Question 3

how to decrease pressure 2

Answer 3

increase sa

decrease force

Question 4

what are the units for pressure

Answer 4

pascals

Question 5

equation for pressure

Answer 5

force/area

Question 6

what happens to the pressure of a liquid as depth increases

Answer 6

it increases

Question 7

what does the pressure in a liquid depend on

Answer 7

depth and density

Question 8

where is the force of a liquid exerted

Answer 8

on the surface in contact with the liquid

Question 9

why is the pressure of a liquid higher with increased depth

Answer 9

there are more particles above that point so there is an increased weight meaning more pressure

Question 10

what is the same in a liquid

Answer 10

the pressure on a straight horizontal line

Question 11

what does the pressure at the bottom of column of liquid depend on

Answer 11

the height of the column,

gravitational field strength and density

Question 12

how to calculate pressure at a certain depth using the column of water above it

Answer 12

pressure = height of column x density x gravitational field strength

Question 13

unit for pressure of a liquid column

Answer 13

pa

Question 14

what is the earths atmosphere

Answer 14

a thin layer of air around the earth

Question 15

what pressure does the earths atmosphere exert at sea level

Answer 15

100 kPa

Question 16

what is atmospheric pressured caused by

Answer 16

air molecules colliding with surface

Question 17

why does the atmospheric pressure decrease with height

Answer 17

the atmosphere gets less dense so there are less air molecules pressing down on that surface
there are fewer air molecules above that point so less weight = less pressure

Question 18

give two examples where atmospheric pressure is used

Answer 18

suction cups

sucking up a straw

Question 19

how does suction work

Answer 19

when you push the cup to the wall there is no air inside it is no air to push it away from the wall
atmospheric pressure acts on the outside of the cup but not inside keeping it up

Question 20

how does a straw work

Answer 20

when you suck you pull all the air out of the straw
the atmospheric pressure acts on the water and pushes it up the straw because there is no resistance- you have sucked all the air that would push water out of the straw

Question 21

what happens to the atmospheric pressure at high altitude

Answer 21

it decreases

Question 22

atmospheric pressure at sea level

Answer 22

100 Pka

Question 23

atmospheric pressure at the top of Mount Everest

Answer 23

30 Pka

Question 24

what is upthrust

Answer 24

the pressure a liquid exerts on an object in it

Question 25

when will an object float

Answer 25

when its weight = upthrust

Question 26

what does whether an object will float depend on

Answer 26

density

Question 27

how do submarines use upthrust

Answer 27

tanks filled with water means weight is more than upthrust so they sink tanks filled with compressed air to rise meaning the submarine weighs less then upthrust

Question 28

why does an object sink

Answer 28

if its more dense than water it means that tits weight is more than the volume of liquid displaced. this means the weight of the object is greater than the force of upthrust

Question 29

why does an object float

Answer 29

it is less dense than water | it weight is less than the volume of water is displaces the weight of the object is less than the force of upthrust

Question 30

what is upthrust

Answer 30

the resultant force of the pressure of the water on the top of an object and the pressure of water on the bottom of an object

Question 31

what is upthrust equal to

Answer 31

the volume of water that is displaced by an object