1-11 Applying forces

• Natuurkunde
• Middelbare school
• vwo
• Leerjaar 3

Applying forces (p. 39)

Stationary

- Writingbook

- Pen, pencil

- Calculator

Mark

- NO

Lessonup

- YES

Schoolbags in

the cupboard

Phones in the phonebag

Lesson goals:

• Explain the difference between a fixed pulley and a loose pulley.
• Calculate work, force or distance with the work formula.
• Reason with profit and loss

        of block and tackle

Fixed pulley

Changes the direction of the force

(not the magnitude of the force)

Work formula 

W = work (Nm)

F = force (N)

s = distance (m)

W=F⋅s

too heavy? ... use a block and tackle

count the number of blocks 

above the loose pulley

Rule

If an object hangs on N amount of ropes, the hoisting force is 

N x greater and the hoisting distance is N x smaller

Profit:

Block and tackle makes the hoisting force 2x bigger

Loss:

2m pulling rope = 

1m hoisting

What is the hoisting force needed at 3?

1

2

3

4

1. 4
2. 6
3. 8
4. 12

49 (p. 37)

Share your answer of exercise 49.
a: ...
b: ...

50 (p. 37)

Share your answer of exercise 50.
a: ...
b: ...
c: ..
d: ...

51 (p. 37)

Share your answer of exercise 50.
a: ...
b: ...
c: ..

What did you
learn today?

Now try

53 and 54 of the digital method