1. WALT: about Hooke‘s Law

2. Who was Hooke English physicist Robert Hooke.
1635, Isle of Wight,—1703, London
In mechanics, and physics Hooke's law of elasticity is an approximation that states that the extension of a spring is in direct proportion with the load applied to it.
Many materials obey this law as long as the load does not exceed the material's elastic limit.

3. Hooke‘s Law
We can see Hooke‘s law in action when we hang masses on the end of a spring.
Each mass will apply a force that stretches the spring.
Each time a 1 N force is applied the spring with extend by the same amount.

4. Demo – Hooke‘s law
Graph to show the extension of a spring when mass is applied.
Extension (cm)
Applied Force (N)

5. Hooke‘s Law
Hooke‘s law states that the extension of spring is directly proportional to the force applied to it.
Results in a straight line graph.
A spring will obey Hooke‘s law until it reaches ist elastic limit.

6. Puzzle
A spring has a weight of 5 N hanging on it and has an extension of 10 cm. What will be the extension if the weight is increased to 15 N ?