# 1-4 Spring constant

Spring constant (p. 14)
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Slide 1: Slide
NatuurkundeMiddelbare schoolvwoLeerjaar 3

This lesson contains 19 slides, with interactive quizzes and text slides.

Lesson duration is: 50 min

## Items in this lesson

Spring constant (p. 14)
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#### Slide 1 -Slide

Lesson goal:
Calcualte the spring constant, force or extention of a spring using the formula.

#### Slide 2 -Slide

Spring constant formula
C=xF
C = spring constant
(N/cm)

F = force
(N)

x = extention of spring
(cm of mm of m)

#### Slide 3 -Slide

What is the unit of C in the formula?
A
N
B
cm
C
N/cm
D
cm/N

#### Slide 4 -Quiz

What is the unit of F in the formula?
A
N
B
cm
C
N/cm
D
cm/N

#### Slide 5 -Quiz

Example 1
A spring is 23,5 cm long if nothing hangs on it and 33,1 cm long if a mass of 350 grams hangs on it. Calculate the spring constant.(6p)

#### Slide 6 -Slide

GIven     x = 33.1-23,5 = 9,6 cm
m = 350 g = 0,35 kg

Calculation  F = mg = 0,35 x 9,8 = 3,43 N

C=xF
=9,63,43
= 0,36 N/cm

#### Slide 7 -Slide

Example 2
The zero position of a spring is 15 cm. If the spring constant is 42 N/m and a force of 6N acts on the spring, what is the length of the spring?

#### Slide 8 -Slide

Given    (zero position) = 15 cm
C = 42 N/m
F = 6N
Asked   length of the spring (15 + x)
Uitwerking
x=CF
=426
= 0,14m = 14 cm
So x = 15 + 14 = 29cm

#### Slide 9 -Slide

Daan does a practical with a spring (C = 35 N/m). First he measures the length of the spring if nothing hangs on it: 27cm. thereafter he hangs a block of 300 gram on the spring. Calculate the total length of the spring.

#### Slide 10 -Slide

Given   C = 35 N/m
zero position = 27 cm
m = 300 g = 0,3 kg
Asked    length of spring (27 + x)
Calculation   F =mg = (0,3)(9,8) = 2,94 N

x=cF
=352,94
= 0,084 m = 8,4 cm
Calculation = 27 + 8,4 = 35,4 cm

#### Slide 11 -Slide

What must you remember when writing a formula...
A
Use the original formula
B
Write that what you want to calculate left of the =

Do question 18
timer
4:00

Do question 19
timer
4:00

#### Slide 16 -Slide

Homework
Do the skillstrainer of 1.2 in the digital method
Answer questions 14 and 17 in the digital method

What have you
learnt today?

#### Slide 18 -Mind map

Conclusion
C=uF
We can calculate this with m x g
calculate with end position - zero position