# Lesson 6

Pressure in liquids — Hydraulics
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Slide 1: Tekstslide
NaskMiddelbare schoolhavo, vwoLeerjaar 2

In deze les zitten 33 slides, met tekstslides.

## Onderdelen in deze les

Pressure in liquids — Hydraulics

#### Slide 1 -Tekstslide

Calculating weight
A) A man with a mass of 80 kilogram (kg) is carrying a box with a mass of 22,5 kilogram (kg). The gravitational field strength on earth is 9.8 Newton/kilogram (N/kg). Calculate the weight of this man and the box together.

B) On the moon this man's weight would be 165 Newton. calculate the gravitational field strength of the moon
W=mg

#### Slide 2 -Tekstslide

Calculating pressure
A woman weighing 76 kg is wearing high heels to the zoo. She goes to see an elephant with a mass of 5221 kg. One of her heels has a total area of 8.4 cm2. One of the elephants feet has an area of 301 cm2.

a) Without making calculations, make an estimation of wether the elephant or the women applies a greater pressure to the ground. Write down your reasoning.

b) Calculate the pressure the women applies to the ground in N/m2.

c) Calculate the pressure the elephant applies to the ground N/m2.
P=AF
W=mg

#### Slide 3 -Tekstslide

Learning goals
At the end of this lesson you can:
• Explain how hydraulics work in your own words
• Name the formula for hydraulics
• Rearrange the formula for hydraulics
• Do calculations on hydraulic systems

1

1
2

#### Slide 9 -Tekstslide

• Fluids are incompressible

1
2

#### Slide 10 -Tekstslide

• Fluids are incompressible

P1=P2
1
2

#### Slide 11 -Tekstslide

• Fluids are incompressible

P1=P2
1
2
A1F1=A2F2

#### Slide 12 -Tekstslide

P1=P2
A1F1=A2F2
Rearranging the formula!

0.01 m2
0.4 m2
20 N

#### Slide 15 -Tekstslide

Worksheet
P1=P2
A1F1=A2F2
If you're done, start reading paragraph 8.5 and working on the workbook exercises of 8.5

#### Slide 16 -Tekstslide

Learning goals
At the end of this lesson you can:
• Explain how hydraulics work in your own words
• Name the formula for hydraulics
• Rearrange the formula for hydraulics
• Do calculations on hydraulic systems

#### Slide 17 -Tekstslide

Pressure in liquids

#### Slide 18 -Tekstslide

This lesson
•  Liquid pressure and upthrust
• Hydraulics
• Worksheet pressure
• Time to work on exercises

#### Slide 19 -Tekstslide

Learning goals
• Describe the basics of liquid pressure in your own words.

• Explain how liquid pressure creates the force upthrust.

• Be able to explain how hydraulic machines work in your own words.

• Be able to do calculations with hydraulic systems

Liquid pressure

#### Slide 24 -Tekstslide

Upthrust
What is upthrust?

Upthrust

Hydraulics

0.01 m2
0.4 m2
20 N

#### Slide 31 -Tekstslide

Working on exercises

#### Slide 32 -Tekstslide

Learning goals
• Describe the basics of liquid pressure in your own words.

• Explain how liquid pressure creates the force upthrust.

• Be able to explain how hydraulic machines work in your own words.

• Be able to do calculations with hydraulic systems