1-9 Levers

• Natuurkunde
• Middelbare school
• vwo
• Leerjaar 3

Levers (p. 26)

Bluetooth 

- ON

- VPN off

Stationary

- Writing book

- Pen, pencil

- Calculator

- iPad

Mark

- NO

Lessonup

- YES

Schoolbags in

the cupboard

Phones in the phone bag

Lesson goals

• Understand and apply the terminology of levers
• Calculate the moment of a force
• Name and apply the law of levers to

           - Calculate force or mass

           - Calculate the length of the arm

Fulcrum, length of arm, force

fulcrum

Force

length of arm

Fulcrum

Better understood if you know that in dutch this is called 'het draaipunt'

Force

You can claculate this with F = m x g

Length of the arm

Distance between the fulcrum and the force

moment = force x length of arm

Force in newton

Length of arm in meters

Moment is in newton meter

M=F⋅r

moment = force x length of arm

Force in newton

Length of arm in meters

Moment is in newton meter

M=F⋅r

F=m⋅g

Length of arm...

from fulcrum to line of action of the force

Law of levers

When a lever is in equilibrium, the sum of the clockwize moments equals the sum of the anticlockwise moments.

Formula

M​1​​+M​2​​+...(anticlockwise)=M​1​​+M​2​​+...(clockwise)

Moment of a force

     anticlockwise                                                                          clockwise

or rotate left                                                                                or rotate                       

                                                                                                                  right

                                               equilibrium

Example 4 (p. 28)

Example

(p. 29)

Example 5 (p. 29)

Now you...

Calculate if this lever is in equilibrium if each mass is 4 kg

What is the unit of moment?

1. Newton
2. meter
3. Newton.meter
4. Newton per meter

Now try 38 

Maak opgaven 39 

Maak opgaven 40

Homework

41 in the digital method (you need the worksheet)

What did you
learn today?