Lesson 5 — Recap force, start pressure

• Nask
• Middelbare school
• havo, vwo
• Leerjaar 2

This lesson

• Recap
  
• Force Quiz
  
• Practice exercise
• Converting units
  

Learning goals

By the end of this lesson you will be able to:

• Explain what pressure is and name the formula for pressure
• Explain what force is and what it can do
• Explain what weight is and how to calculate it
• Convert m² to cm² and vice versa and convert N/m² to N/cm² and vice versa

Recap

• What did we cover previous lesson?
• What is pressure?
  

Pressure

A measure of force applied to the surface of an object 

Quantity	Unit
Pressure (P)	Pascal (Pa)
Force (F)	Newton (N)
Area (A)	m 2

Pressure=​Area​​Force​​

P=​A​​F​​

Formula

Force Quiz

What is Force?

1. A push or pull that can change an objects shape, but not its movement
2. A push or pull that can change the way an object moves, but not its shape
3. A push or pull that can change the way an object moves or its shape
4. A push or pull that can not change the way an object moves nor its shape

Force is a push or pull

That can:

• Accelerate or decelerate an object
• Change the direction of a movement
• Change the shape of an object

Unit: Newton (N)

What is weight? And in what unit is it given?

1. The mass of a specific object, given in kilogram
2. The magnitude of the force of earths gravity on a specific object, given in Newton
3. The magnitude of the force of earths gravity on a specific object, given in kilogram
4. The mass of a specific object, given in Newton

What is the formula to calculate weight?

1. Weight = mass x gravitational field field strength
2. Weight = force x gravitational field strength
3. Weight = mass x force
4. Weight = (gravitational field strength)^2

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

Pressure 

The amount of force applied to the surface of an area.

• Unit: Pascal
  
• 1 Pascal = 1 N/m²

Converting units

Converting m² to cm²

Converting N/m² to n/cm²

Converting units

Exercise 1

• 1 cm² = 0.0001 m²
  
• 1 m² = 10000 cm²
  
• 5 cm² = 0.0005 m²
  
• 5 m² = 50000 cm²
  
• 0,1 m² = 1000 cm²
  
• 0,1 cm² = 0,00001 m²
  

Exercise 2

• 1 N/cm² = 10000 N/m²
  
• 1 N/m² = 0,0001 N/cm²
  
• 5 N/cm² = 50000 N/m²
  
• 5 N/m² = 0,0005 N/cm²
  
• 0,1 N/m² = 0,00001 N/cm²
  
• 0,1 N/cm² = 1000 N/m²
  

Converting units

Exercise 1

• 1 cm² = 0.0001 m²
  
• 1 m² = 10000 cm²
  
• 5 cm² = 0.0005 m²
  
• 5 m² = 50000 cm²
  
• 0,1 m² = 1000 cm²
  
• 0,1 cm² = 0,00001 m²
  

Exercise 2

• 1 N/cm² = 10000 N/m²
  
• 1 N/m² = 0,0001 N/cm²
  
• 5 N/cm² = 50000 N/m²
  
• 5 N/m² = 0,0005 N/cm²
  
• 0,1 N/m² = 0,00001 N/cm²
  
• 0,1 N/cm² = 1000 N/m²
  

Converting units

Exercise 1

• 1 cm² = 0.0001 m²
  
• 1 m² = 10000 cm²
  
• 5 cm² = 0.0005 m²
  
• 5 m² = 50000 cm²
  
• 0,1 m² = 1000 cm²
  
• 0,1 cm² = 0,00001 m²
  

Exercise 2

• 1 N/cm² = 10000 N/m²
  
• 1 N/m² = 0,0001 N/cm²
  
• 5 N/cm² = 50000 N/m²
  
• 5 N/m² = 0,0005 N/cm²
  
• 0,1 N/m² = 0,00001 N/cm²
  
• 0,1 N/cm² = 1000 N/m²
  

Converting units

Exercise 1

• 1 cm² = 0.0001 m²
  
• 1 m² = 10000 cm²
  
• 5 cm² = 0.0005 m²
  
• 5 m² = 50000 cm²
  
• 0,1 m² = 1000 cm²
  
• 0,1 cm² = 0,00001 m²
  

Exercise 2

• 1 N/cm² = 10000 N/m²
  
• 1 N/m² = 0,0001 N/cm²
  
• 5 N/cm² = 50000 N/m²
  
• 5 N/m² = 0,0005 N/cm²
  
• 0,1 N/m² = 0,00001 N/cm²
  
• 0,1 N/cm² = 1000 N/m²
  

Converting units

Exercise 1

• 1 cm² = 0.0001 m²
  
• 1 m² = 10000 cm²
  
• 5 cm² = 0.0005 m²
  
• 5 m² = 50000 cm²
  
• 0,1 m² = 1000 cm²
  
• 0,1 cm² = 0,00001 m²
  

Exercise 2

• 1 N/cm² = 10000 N/m²
  
• 1 N/m² = 0,0001 N/cm²
  
• 5 N/cm² = 50000 N/m²
  
• 5 N/m² = 0,0005 N/cm²
  
• 0,1 N/m² = 0,00001 N/cm²
  
• 0,1 N/cm² = 1000 N/m²
  

Converting units

Exercise 1

• 1 cm² = 0.0001 m²
  
• 1 m² = 10000 cm²
  
• 5 cm² = 0.0005 m²
  
• 5 m² = 50000 cm²
  
• 0,1 m² = 1000 cm²
  
• 0,1 cm² = 0,00001 m²
  

Exercise 2

• 1 N/cm² = 10000 N/m²
  
• 1 N/m² = 0,0001 N/cm²
  
• 5 N/cm² = 50000 N/m²
  
• 5 N/m² = 0,0005 N/cm²
  
• 0,1 N/m² = 0,00001 N/cm²
  
• 0,1 N/cm² = 1000 N/m²
  

Converting units

Exercise 1

• 1 cm² = 0.0001 m²
  
• 1 m² = 10000 cm²
  
• 5 cm² = 0.0005 m²
  
• 5 m² = 50000 cm²
  
• 0,1 m² = 1000 cm²
  
• 0,1 cm² = 0,00001 m²
  

Exercise 2

• 1 N/cm² = 10000 N/m²
  
• 1 N/m² = 0,0001 N/cm²
  
• 5 N/cm² = 50000 N/m²
  
• 5 N/m² = 0,0005 N/cm²
  
• 0,1 N/m² = 0,00001 N/cm²
  
• 0,1 N/cm² = 1000 N/m²
  

Converting units

Exercise 1

• 1 cm² = 0.0001 m²
  
• 1 m² = 10000 cm²
  
• 5 cm² = 0.0005 m²
  
• 5 m² = 50000 cm²
  
• 0,1 m² = 1000 cm²
  
• 0,1 cm² = 0,00001 m²
  

Exercise 2

• 1 N/cm² = 10000 N/m²
  
• 1 N/m² = 0,0001 N/cm²
  
• 5 N/cm² = 50000 N/m²
  
• 5 N/m² = 0,0005 N/cm²
  
• 0,1 N/m² = 0,00001 N/cm²
  
• 0,1 N/cm² = 1000 N/m²
  

Converting units

Exercise 1

• 1 cm² = 0.0001 m²
  
• 1 m² = 10000 cm²
  
• 5 cm² = 0.0005 m²
  
• 5 m² = 50000 cm²
  
• 0,1 m² = 1000 cm²
  
• 0,1 cm² = 0,00001 m²
  

Exercise 2

• 1 N/cm² = 10000 N/m²
  
• 1 N/m² = 0,0001 N/cm²
  
• 5 N/cm² = 50000 N/m²
  
• 5 N/m² = 0,0005 N/cm²
  
• 0,1 N/m² = 0,00001 N/cm²
  
• 0,1 N/cm² = 1000 N/m²
  

Converting units

Exercise 1

• 1 cm² = 0.0001 m²
  
• 1 m² = 10000 cm²
  
• 5 cm² = 0.0005 m²
  
• 5 m² = 50000 cm²
  
• 0,1 m² = 1000 cm²
  
• 0,1 cm² = 0,00001 m²
  

Exercise 2

• 1 N/cm² = 10000 N/m²
  
• 1 N/m² = 0,0001 N/cm²
  
• 5 N/cm² = 50000 N/m²
  
• 5 N/m² = 0,0005 N/cm²
  
• 0,1 N/m² = 0,00001 N/cm²
  
• 0,1 N/cm² = 1000 N/m²
  

Converting units

Exercise 1

• 1 cm² = 0.0001 m²
  
• 1 m² = 10000 cm²
  
• 5 cm² = 0.0005 m²
  
• 5 m² = 50000 cm²
  
• 0,1 m² = 1000 cm²
  
• 0,1 cm² = 0,00001 m²
  

Exercise 2

• 1 N/cm² = 10000 N/m²
  
• 1 N/m² = 0,0001 N/cm²
  
• 5 N/cm² = 50000 N/m²
  
• 5 N/m² = 0,0005 N/cm²
  
• 0,1 N/m² = 0,00001 N/cm²
  
• 0,1 N/cm² = 1000 N/m²
  

Converting units

Exercise 1

• 1 cm² = 0.0001 m²
  
• 1 m² = 10000 cm²
  
• 5 cm² = 0.0005 m²
  
• 5 m² = 50000 cm²
  
• 0,1 m² = 1000 cm²
  
• 0,1 cm² = 0,00001 m²
  

Exercise 2

• 1 N/cm² = 10000 N/m²
  
• 1 N/m² = 0,0001 N/cm²
  
• 5 N/cm² = 50000 N/m²
  
• 5 N/m² = 0,0005 N/cm²
  
• 0,1 N/m² = 0,00001 N/cm²
  
• 0,1 N/cm² = 1000 N/m²
  

Converting units

Exercise 1

• 1 cm² = 0.0001 m²
  
• 1 m² = 10000 cm²
  
• 5 cm² = 0.0005 m²
  
• 5 m² = 50000 cm²
  
• 0,1 m² = 1000 cm²
  
• 0,1 cm² = 0,00001 m²
  

Exercise 2

• 1 N/cm² = 10000 N/m²
  
• 1 N/m² = 0,0001 N/cm²
  
• 5 N/cm² = 50000 N/m²
  
• 5 N/m² = 0,0005 N/cm²
  
• 0,1 N/m² = 0,00001 N/cm²
  
• 0,1 N/cm² = 1000 N/m²
  

Exercise – Homework

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=​A​​F​​

W=m⋅g

Homework

• The exercise on the previous slide
  
• Read 8.2
  
• The yellow block exercises of 8.2
  

Learning goals

By the end of this lesson you will be able to:

• Explain what pressure is and name the formula for pressure
• Explain what force is and what it can do
• Explain what weight is and how to calculate it
• Convert m² to cm² and vice versa and convert N/m² to N/cm² and vice versa