1-2 Drawing forces and a centre of gravity

• Natuurkunde
• Middelbare school
• vwo
• Leerjaar 3

Drawing forces and a 

centre of gravity (p. 9)

Bluetooth 

- ON

- VPN off

Stationary

- Text book and writing book

- Pen, pencil

- Calculator

- iPad Geotriangle

Mark

- NO

Lessonup

- YES

Schoolbags in

the cupboard

Phones in the phonebag

Lessongoals:

• Draw or sketch a force diagram.
• Indicate where the centre of gravity lies.

Drawing a force

A force has a

- magnitude

- direction

- point of application

Any quality with these properties is called a vector.

Force scale

First choose a force scale, eg. 1 cm      5 N

- This means that an arrow with a length of 1 cm represents a force of 5 N and therefore an arrow with a length of 3 cm represents a force of 15 N.

Example

Draw a force of 20N to the right.

Centre of gravity

Point where you can imagine gravity as being applied.

An object will topple over if the centre of

gravity is not above the plane it is resting 

on.

Plane it is resting on

Which one of the following factors is insignificant when drawing a force?

1. Length
2. Thickness
3. Point of application
4. Direction

Where is the centre of gravity?

A

B

C

1. A
2. B
3. C

Do question 7 (p. 12)

On the following slide you will hand in a photo of your answer

Make a photo of your answer to question 5 and hand it in.

Do question 8 (p. 13)

Do question 10 (p. 13)

Do question 12 (p. 13)

What have you
learned today?

Conclusion:

• A vector has magnitude, direction and a point of application.
• An arrow representing a force therefore has a length, direction and a starting point.
• The centre of gravity is the point 

       where the mass of the object is in 

       equilibrium.