1-1 Introduction and forces

• Natuurkunde
• Middelbare school
• vwo
• Leerjaar 3

Introduction and forces

(p. 8)

Stationary

- Book and writingbook

- Pen, pencil

- Calculator

- iPad

REPORT

- NO

Lessonup

- YES

Schoolbag in

the cupboard

Phones in the phonebag

Forces can do three things:

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

       shape of an

       object

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?

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

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