1-1 Introduction and forces

• Natuurkunde
• Middelbare school
• vwo
• Leerjaar 3

Introduction and forces

(p. 8)

Bluetooth 

- ON

- VPN off

Stationary

- Book and writingbook

- Pen, pencil

- Calculator

- iPad

REPORT

- NO

Lessonup

- YES

Schoolbag in

the cupboard

Phones in the phonebag

LESSONUP:

- Download the lessonup app from the appstore.

- Register, and type in the following classcode:

A3X - qxbwq

C3X - jncws

Google classroom

A3X - v8bnxk

C3X - f347gg2

Lessongoals:

• Discussion of the class rules. 
• Name three things forces can do.
• Name the two types of deformation. 
• Explain which deformation is applicable.
• Name the types of forces.
• Calculate gravitational force.

Rules

• We respect each other 
  
• We keep the class clean
  

       - We dont eat in the class

       - You may have a bottle of water with you

• We do our best 
  

      - Be prepared for a lesson

      - Give your best effort

What do you need in every lesson:

• For all the lessons bring an A4 writing book with 1 x 1 blocks and a textbook even when you are writing a test.
  
• Keep a file for your tests and handouts (alternatively you can take a photo of the mark of your test).
  

• CALCULATOR, a Casio!! You are not allowed to use your mobile phone or iPad as calculator because you must learn how to use your calculator in the class. 
  
• Stationary such as a pen, pencil and ruler/ geotriangle.
• Sometimes you need a pair of compasses to draw a circle, so also have that with you. 
  

Neatness

• Begin a new lesson with a heading and a date in your writing book and underline your work at the end of a lesson. 
  
• Write with a black or blue pen, and make diagrams and graphs with a pencil.
  
• You will get a mark for your writing book.
  

Forces can do three things:

• Change the speed of an object
  
• Change the direction of an object
  
• Change the  

       shape of an

       object

There are two kinds of deformation

• Elastic deformation: 

       Original shape of an object 

       returns when force is removed.

• Plastic deformation: 

       The deformation is 
       permanent.

Types of forces:

• Muscular strength
  
• Resistance or resilience
  

• Tention (rope)


• Gravity
  
• Magnetic force
• Friction

                       or

Forces are measured with a dynamometer in Newton.

F​musc​​

F​r​​

F​T​​

F​gr​​

F​f​​

f

Calculating gravitational force:

To calculate the gravitational force on an object we use the formula... 

F = mg 

where g = 9.8 N/kg

Calculating gravity

If you have the mass of an object in kg, 

then you can calculate the force of gravity with:

mass x 9.8

F​gr​​

Example 1

What is the gravitational force of an object with a mass of

 550 grams?

Example 2

If the gravity on an object is 900 N, what then is the mass of the object?

What kind of
deformation
can be seen here

1. Elastic deformation
2. Plastic deformation

What kind of
deformation
can be seen here?

1. Elastic deformation
2. Plastic deformation

What kind of deformation can be seen here?

1. Elastic deformation
2. Plastic deformation

Which of the following is NOT an effect of forces:

1. Increase speed
2. Change direction
3. Change shape
4. Attract an object

Which of the following is NOT a type of force?

1. Muscular strength
2. Mass force
3. Magnetic force
4. Resilience

What can be used to measure forces?

1. Ruler
2. Dynamometer
3. Newton scale
4. An estimation

What must be the unit of mass if you want to calculate force?

1. ton
2. kg
3. g
4. mg

When do you divide with 9,8 and when do you multiply with 9,8?

What is the gravitational force on a tennis ball with a mass of 56 grams?

1. 548,8 N
2. 5,7 N
3. 0,549N
4. 0,57N

What is the mass of an antelope with a gravitational force of 2 499 N?

1. 255 kg
2. 2,55 kg
3. 24 490 kg
4. 24,49 kg

Do question 3 (p. 12)

Do question 5 (p. 12)

What did you
learn today?

Conclusion:

• Forces can change the speed, direcition 

     and shape of an object.

• With elastic deformation the object returns to its original shape and with plastic deformation the deformation is permanent.
• Types of forces: Muscular strength, resilience, gravitational force and magnetic force.

F=ma