2A - Elasticiteit, uitrekking en hooke's law

• Natuurkunde / Scheikunde
• Middelbare school

This lesson

• Elasticity and extension
• Discussing the practical
• Hooke's law

 – at the end of this lesson you ...

• can correctly explain what elasticity and extension are.
• can Understand what the graph of the practical showed you.
• know hoooke's law, can rearrange it and can apply it correctly

Goals

What is extension?

Extension = final lenght – original length

What does elasticity mean?

Elasticity

When something regains it’s original shape after having changed shape

Discussing

the practical

Hooke's Law

Force  =  spring constant  x  extension

F=k⋅x

Exersise!

Rearrange hooke's law

The formula to calculate
the spring constant is...

The formula to calculate
the extension is....

Exersise

1) What is the magnitude of the force required to stretch a 20 cm-long spring, with a spring constant of 100 N/m, to a length of 21 cm?

Exersise  – solution

1) What is the magnitude of the force required to stretch a 20 cm-long spring, with a spring constant of 100 N/m, to a length of 21 cm?

Solution

x (Extension) = 21 cm - 20 cm = 1 cm

k = 100 N/m

F = ?

F = 100 N/m x 1 cm = 100 Newton

F=k⋅x

Exersise  – solution

What is the magnitude of the force required to stretch a 20 cm-long spring, with a spring constant of 100 N/m, to a length of 21 cm?

Solution

x (Extension) = 21 cm - 20 cm = 1 cm

k = 100 N/m

F = ?

F = 100 N/m x 1 cm = 100 Newton

F=k⋅x

What if I dubble the spring constant? BUt apply the same force?

The homework

• §2.3 exersise 1b.
• All exersises of §2.4.

Working independently

 at the end of this lesson you ...

• can correctly explain what elasticity and extension are.
• can Understand what the graph of the practical showed you.
• know hoooke's law, can rearrange it and can apply it correctly

Goals