# Lesson 5

Pressure in liquids
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Slide 1: Tekstslide

In deze les zitten 16 slides, met tekstslides.

## Onderdelen in deze les

Pressure in liquids

#### Slide 1 -Tekstslide

This lesson
• Recap + exercise
• Fluid pressure
• Working on exercises

#### Slide 2 -Tekstslide

Learning goals
• Name the formulas for pressure and weight and be able to apply them.

• Explain what is meant by liquid pressure.

• Explain why there is greater pressure at the bottom of the sea than at the surface.

Recap

#### Slide 4 -Tekstslide

P3 — Pressure & density
• Pressure is the result of force being applied to a surface.
• Force is measured in newtons (N)
• area is measured in square meters (m2)

•  The formula for pressure is:

• The unit of pressure is pascal (Pa). One pascal is 1 N/m2
Pressure=areaforce

#### Slide 5 -Tekstslide

P3 — Pressure & density
Weight:
• With how much force an object is pulled down

Weight=massgravitationalfieldstrength
W=mg

#### Slide 6 -Tekstslide

Pressure
ρ=AF
pressure=AreaForce
Pressure (ρ): Pascal (Pa – N/m2), N/cm2
Force (V): N
Area (m): m2, cm2

#### Slide 7 -Tekstslide

Pressure
w=mg
Weight=massgravitationalfieldstrength
Weight (W): Newton (N)
Mass (m): kilogram (kg)
Gravitational field strength (g): N/kg

#### Slide 8 -Tekstslide

Exercise
Two scenario's:
• 1) A man is standing on 7,60 cm thick ice. He has a mass of 88 kg and one of his feet has an area of 0.0047 m2

• 2) A man is laying flat on his back on 7,60 cm thick ice. He has a mass of 88 kg. His body touching the ice has an area of 0.0915 m2

Ice of this thickness breaks at about 18.000 Pascal (N/m2).
The gravitational field strength on Earth is 9.8 N/kg

a) Calculate the pressure for each scenario.
b) Explain wether the ice will break or not.

Liquid pressure

#### Slide 11 -Tekstslide

Upthrust
What is upthrust?

Upthrust

Liquid pressure

And upthrust

#### Slide 14 -Tekstslide

To-do for the coming week
• 8.3
• 8.4

Do:
• 8.3 yellow block + workbook exercises
• 8.3 yellow block + workbook exercises

Due for the seconds lesson of next week

#### Slide 15 -Tekstslide

Learning goals
• Name the formulas for pressure and weight and be able to apply them.

• Explain what is meant by liquid pressure.

• Explain why there is greater pressure at the bottom of the sea than at the surface.