Science, Physics - Forces & Pressure

Question 1

what is pressure

Answer 1

• when there is something on a surface that exerts force on it because of its weight
• a measure of how much force is applied over a certain area

Question 2

N/m2 meaning

Answer 2

Pascal

Question 3

finding force (N)

Answer 3

pressure (N/m2) x area (m2)

Question 4

finding pressure (N/m2)

Answer 4

force (N) / area (m2)

Question 5

finding area (m2)

Answer 5

force (N) / pressure (N/m2)

Question 6

how to increase pressure

Answer 6

reducing area

Question 7

how to decrease pressure

Answer 7

increase area

Question 8

pressure in liquids

Answer 8

• weight of liquid causes pressure in container
• also causes pressure to any objects in the liquid
• the forces between particles in the liquid acting over an area

Question 9

properties of pressure in liquids

Answer 9

1. pressure acts in all directions
2. pressure increases with depth
3. depends upon the density of the liquid
4. pressure doesn’t depend upon the shape of the container.

Question 10

hydraulics

Answer 10

• mechanical function that operates through the force of liquid (incompressible)
• can make forces bigger (e.g. hydraulic car jack)

Question 11

fluids

Answer 11

• air is a fluid
• liquid and gases are fluids
• no fixed shape
• particles in a fluid exert a pressure on surfaces

Question 12

why does a balloon get bigger as it blown up

Answer 12

gets filled up with air particles => start to collide with each other => creates a force (gas pressure) => expands balloon

Question 13

finding fluid/gas pressure (Nm2)

Answer 13

force (N) / area (m2)

Question 14

relationship between pressure, volume & temperature

Answer 14

*imagine gas trapped in a cylinder by a piston

piston pushed in => volume decreases => no room for gas particles (squashed) => increases pressure

Question 15

decreased volume = ______

Answer 15

increased pressure

*pressure of gas is inversely proportional to its volume (totally opposite)

Question 16

relationship of volume and temperature

Answer 16

high temperature => particles gain energy (move faster) => collide with each other = > increased pressure

Question 17

pressure depends on two factors …

Answer 17

temperature and quantity of particles

Question 18

pivot

Answer 18

a point where objects can turn using force

Question 19

lever

Answer 19

a long bar that pivots

Question 20

applying force

Answer 20

pushing down on one side of the lever

Question 21

load

Answer 21

the object on the other end of the lever which moves up when force is applied

Question 22

using a lever

Answer 22

• changes the force
• makes objects easier to move

Question 23

distance from the pivot

Answer 23

the longer the distance (from the pivot), the greater force

Question 24

moment

Answer 24

• turning effect of a force
• described as clockwise and anti-clockwise

Question 25

finding moment

Answer 25

moment = force x distance from point

Question 26

equilibrium

Answer 26

• state of balance
• clockwise moments and anticlockwise moments are equal