8 pressure my ass to study i dont think so

Question 1

Effect of force acting on surface depends on

Answer 1

Surface area of which the force is applied

Question 2

What is pressure

Answer 2

Force per unit area (direction of force is perpendicular to surface area)

Question 3

What is the formula for pressure & SI unit

Answer 3

Force (N) / Surface area (m^2)
pascal (Pa)
1 Pa = 1 newton per square metre

Question 4

What does the kinetic theory of gas relate to air pressure

Answer 4

Air molecules always move about freely & collide w/ walls of its container
The frequency of collision -> force that pauses against the walls = air pressure

Question 5

Factors affecting air pressure

Answer 5

Volume
Temperature

Question 6

State relation between volume & air pressure

Answer 6

Closed container compressed -> volume reduced -> air particles collide more frequently w/ walls -> air pressure increases

Question 7

What is used to measure air pressure

Answer 7

Bourdon gauge

Question 8

What is relation between temperature and air pressure

Answer 8

Air temperature increase -> air particles move faster -> collide more frequently w/ walls -> greater force

Question 9

When a drink is sucked out of its packet why will the packet compress

Answer 9

Drink inside packet becomes partial vacuum -> air pressure inside decrease
Higher air pressure outside -> press onto packet -> compress it

Question 10

What is atmospheric pressure

Answer 10

Air pressure outside
Exerted by atmosphere on surface of Earth & all objects on Earth

Question 11

What is the principle of plunger

Answer 11

1. Plunger pressed against sink -> air inside force out -> low pressure
2. Pull up plunger -> high pressure in pipe pushes out stuck blockage

Question 12

What is the principle of Magdeburg Hemisphere

Answer 12

1. Air in hemisphere pumped out -> space becomes vacuum (pressure = 0)
2. two hemisphere cannot be separated -> atmospheric pressure outside exert very strong force on hemisphere

Question 13

What is the principle of a straw

Answer 13

1. Air in straw is sucked -> pressure invide reduced
2. Higher pressure outside -> push drink into straw -> into mouth

Question 14

What is the principle of syphon

Answer 14

1. End of tube B -> lower than tube A -> water flow out
2. Water flows out -> low air pressure in tube
3. Atmospheric pressure pushes water into tube -> water flows out continuously

Question 15

What is the principle of syringe

Answer 15

1. Piston pulled up -> volume of air increases -> low air pressure in cylinder
2. Higher air pressure outside push liquid into syringe

Question 16

What is the principle of vacuum cleaner

Answer 16

1. Switch on -> fan in vacuum push air out -> air pressure in vacuum cleaner drops
2. High atmospheric pressure push air & dust into vacuum cleaner

Question 17

Explain how to pour condensed milk out easy from a tin can

Answer 17

Make hole on top so air can flow through -> balance air pressure inside and outside

One hole- milk does not flow out easily -> high pressure outside can
Two holes- milk floes out easily-> air pressure inside & outside is equal

Question 18

Other than making another hole, how to pour condense milk out

Answer 18

Repeatedly pour and put down to let the sir reenter

Question 19

What is relation between atmospheric pressure and altitude

Answer 19

Ap decrease - altitude increase
Gravitational attraction - air molecules close to surface of earth are pulled together by GA -> pressure rise
Higher altitude -> air molecules less affected by GA -> less heavy & expands easily

Question 20

Liquid pressure depends on

Answer 20

Depth

Question 21

Why do bubbles become larger as they rise to surface

Answer 21

Decreasing liquid pressure as depth decreases

Question 22

How are walls of dam designed

Answer 22

Thicker at base - withstand high water pressure at the base

Question 23

Why to divers wear special suit

Answer 23

Withstand high water pressure

Question 24

What is body of submarine made out of and why

Answer 24

Strong material
Will not be crushed by high water pressure

Question 25

What is condition for syphon to work

Answer 25

Tube siphoning out water must be lower than other tube