pressure

Question 1

pressured is defined as

Answer 1

force per unit of area or concentration of a force

Question 2

If a force is spread over a large area it will result in

Answer 2

a small pressure.

Question 3

If it is spread over a small area it will result in a

Answer 3

large pressure

Question 4

Pressure is related to force and area by the equation:

Answer 4

Question 5

When you push a drawing pin, it goes into the surface (rather than your finger) because

Answer 5

the force on the surface is more concentrated

Question 6

The units of pressure depend on the

Answer 6

units of area

Question 7

if the area is measured in cm2 then the pressure will be in

If the area is measured in m2 (and the force in N), then the pressure will be in

Pressure can also be measured in

Answer 7

then the pressure will be in

N/cm2.

N/m2.

pascals, Pa

Question 8

1 Pa is the same as

Answer 8

1 N/m2

Question 9

Answer 9

Question 10

pressure cann be increased by

Answer 10

icreasing the force and decreasing the area

Question 11

why a sharp knife cuts bread more easily than a blunt knife

Answer 11

page 76 answer

Question 12

do problem page 77

Question 13

pressure has the following properties in liquids

Answer 13

The pressure in the liquid depends upon a couple of factors:

The depth of the liquid

The density of the liquid

The bigger either of these factors, the greater the pressure.

When an object is immersed in a liquid, the liquid will exert a pressure, squeezing the object.

This pressure is exerted evenly across the whole surface of the liquid, and in all directions.

Question 14

The size of this pressure depends upon the

Answer 14

density (ρ) of the liquid, the depth (h) of the liquid or the object that contains it and the gravitational field strength (g):

Question 15

pressure in liquids formula

Answer 15

Question 16

In the above equation:

Pressure is in

Depth is in

Density is in

The gravitational field strength on Earth is approximately

Answer 16

pascal

metres

kg/m3.

10 N/kg.

Question 17

Answer 17

Question 18

you measure pressure by using a

Answer 18

Barometers and Manometers

Question 19

A barometer is

Answer 19

a device that is used to measure air pressure.

Question 20

A manometer is

Answer 20

used to measure gas pressures, apart from atmospheric pressure

Question 21

A simple barometer consists of

Answer 21

a column of mercury in an inverted tube, sat in a tray of mercury exposed to the atmosphere.

Question 22

draw a simple mercury barometer, used to measure atmospheric pressure

Answer 22

Question 24

The weight of the mercury in the tube is balanced by

Answer 24

atmospheric pressure pushing down on the mercury in the tray.

Question 25

If atmospheric pressure increases,

Answer 25

a greater length of mercury can be supported in the tube.

Question 26

If atmospheric pressure decreases

Answer 26

then less mercury will be supported in the tube.

Question 27

A simple manometer consists of

Answer 27

a U-tube containing mercury.

Question 28

drAw simple manometer, consisting of mercury in a U-tube

Answer 28

Question 29

do problem at page 81

Question 30

A simple manometer consists of a U-tube containing mercury.

describe it

Answer 30

One end of the U-tube is open to the atmosphere.

The other end is connected to the pressure that is to be measured.

As the measured pressure increases, the mercury is pushed around the U-tube:
The greater the pressure, the further it is pushed.

Question 31

Answer 31

Question 32

the space above the mercury in a barometer is

so no… on the mercury at hte top of the tube

t

Answer 32

vacuum

no pressure

Question 33

the height from the top of the mercury in the dish to the top of the mercury at the top of the tube can be used to calculate

Answer 33

air atmosphere

Question 34

the height fluctuates around

Answer 34

760mm

Question 35

atmospher. pressure has properties:

Answer 35

its effect acts equally in all directions

it decreases \as altitude increases because the AIR molecules \become further apart

it increases as altitude decreases as air molecules become closer together

Question 36

why we use mercury in a barometer and not water

Answer 36

because mercury is denser

if we used water we would need a very long instrument

Question 37

atmospheric pressure can be stated in

Answer 37

millimetres of mercury

mmHg

Question 38

in a manometer the height difference tells you

Answer 38

how much above atmospheric pressure the actual pressure of the gas is

Question 39

in a manometer left side is attached to a

Answer 39

gas supply

Question 40

in a manoometer the liquid moves if

the greater the …the bigger the height difference

Answer 40

there is a pressure difference

pressure difference