chapter 6 pressure

Question 1

pressure

Answer 1

pressure is the force acting per unit area

Question 2

formula for pressure

Answer 2

p= f/a

p= pressure (pa)
f= force (n)
a= contact area (m^3)

Question 3

SI unit for pressure

Answer 3

newton per square meter (n/m^2)

Question 4

other commonly used units of pressure

Answer 4

kilopascal (1kPa=10^3 Pa)
megapascal (1MPa=10^6 Pa)
standard atmosphere (1atm=101 325 Pa=101.325 kPa)

Question 5

relationship between pressure, force and area

Answer 5

• the greater the magnitude of the force, the greater the pressure
• the smaller the contact area, the larger the pressure

Question 6

is pressure a scalar or vector quantity

Answer 6

scalar quantity
(inky the force perpendicular to the contact area is considered when calculating pressure)

Question 7

what is the pascal principle

Answer 7

if a pressure applied to an enclosed liquid, the pressure transmitted to all other parts of the liquid is undiminished

Question 8

density

Answer 8

density is defined as mass per unit volume

Question 9

formula for density

Answer 9

ρ = m/v

ρ= density
m= mass (kg)
v= volume (m^3)

Question 10

SI unit for density

Answer 10

kilogram per cubic meter (kg/m^3)

Question 11

how do you determine the density of a liquid

Answer 11

1. Weigh an empty graduated measuring cylinder,
2. Pour the liquid into the measuring cylinder and weigh both the measuring cylinder and the liquid
3. Determine the mass of the liquid by subtracting the reading in step 1 from the reading in step 2,
4. The volume of the liquid can be measured using the measuring cylinder.
5. The density of the liquid can be calculated using: Density of liquid = mass of liquid / volume of liquid

Question 12

determining the density of solids

Answer 12

measure the solids mass using an electronic mass balance and volume using a measuring cylinder by immersing the solid in the water and measuring its displacement

Question 13

pressure in a liquid increases with __

Answer 13

depth

Question 14

pressure between 2 levels in a liquid is

Answer 14

p= hρg

h= height (m) ρ= density (kg/m^3) g=gravitational field strength (n/kg)

Question 15

steps in measuring pressure using a mercury barometer

Answer 15

1. the inverted glass tube is pushed into the mercury
2. atmospheric pressure forces the mercury into the glass tube
3. the column of mercury has a pressure equal to atmospheric pressure

Question 15

what can be used to measure pressure

Answer 15

mercury barometer

Question 16

step 1 of using mercury barometer

Answer 16

the inverted glass tube is pushed into the mercury

Question 17

step 2 of using mercury barometer

Answer 17

atmospheric pressure forces the mercury into the glass tube

Question 18

step 3 of using a mercury barometer

Answer 18

the column of mercury has a pressure equal to atmospheric pressure

Question 19

how does a mercury barometer work

Answer 19

the vertical height of the mercury column depends only on the atmospheric pressure

Question 20

why is using a mercury barometer effective in measuring atmospheric pressure

Answer 20

it does not depend on the size of the tube used or now deep the tube is placed into the trough of mercury as the vertical height of the mercury column remains the same

Question 21

how will atmospheric pressure change when taken to an elevated region

Answer 21

atmospheric pressure is lower

Question 22

how can we tell that atmospheric pressure has lowered using a mercury barometer

Answer 22

the mercury column will be shorter.

A shorter height of the barometer translates to a lower pressure being measured.