Pressure And Density

Question 1

Air pressure

Answer 1

101000Pa

Question 2

Pressure equation

Answer 2

Pressure = force(w) ➗area (cm2)

Question 3

If the same force is being exerted over a smaller area the pressure will be

Answer 3

Greater

Question 4

Things that need to exert high pressure to work well (tip: will need to be able to exert force over smaller area)

Answer 4

Scissors, knives etc

Question 5

Why do tractors have large wheels?

Answer 5

• Designed to move over mud
• large tyres spread vehicles weight
• force acting over larger area
• less pressure so tractor less likely to sink into mud

Question 6

Density equation

Answer 6

Density = mass ➗volume

G/cm2, kg/m2) (g,kg) (Cm3, m3

Question 7

For an object to be able to float, it needs..

Answer 7

A density less than that of the liquid in which it is placed

Question 8

The molecules in a gas are in a state of

Answer 8

Constant motion 
(Also called random thermal motion or Brownian motion)

Question 9

How does air exert pressure on you?

Answer 9

Each time an air particle collides with your body it exerts a tiny force. The number of collisions is huge, so overall a large force is exerted

Question 10

Weight

Answer 10

Mass ➗ 100

Question 11

Units of pressure

Answer 11

Pascals

Question 12

(Change in) pressure

Answer 12

(Change in) height x density of fluid x strength of gravity

Question 13

Evaporation

Answer 13

When particles escape from a liquid and become gas particles

Question 14

Particles near the surface of a liquid can escape and become gas particles if:

Answer 14

• the particles are travelling in the right direction to escape the liquid
• the particles are travelling fast enough(they have enough KE) to overcome the attractive forces of the other particles in the liquid