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Hooke's Law

Ooi Yeuan Yang 32420811

Hooke's Law

This law is named after Robert Hooke, he is a British Physicist that introduce Hooke's Law, he state that "The force needed to extend or compress a spring by some distance is proportional to that distance."Matt Williams, 2015, in Hooke's Law.

https://www.biography.com/scholar/robert-hooke

Three material are represent by y1, y2 and z, the value tells us the deformation of spring by mm, and x is the force applied (N). By using the formula F = -kx, we can calculate spring's constant, force applied and extension of spring.

We can get y2 and z value by using excel built in formula:

y2: =(1.5583+0.5)*A2+0.2

z: =POWER(A2,3)+1.375

Graph

                                               Graph 1                                                                                     Graph 2

Graph 1 is material 1 and 2, it shows linearity while graph 2 which is material 3 has a curve, exponential-like graph. Therefore, we can conclude that material 1 and 2 obey the Hooke's Law while material 3 does not obey Hooke's Law. 

https://en.wikipedia.org/wiki/Hooke%27s_law

(This is a diagram on how spring should look like as if it obey Hooke's Law.)

What is happening physically?

When spring is applied with force, shape and size of the spring will change, it depends on the spring constant. Two spring can have same shape and size initially and when same amount of force is applied at the same spot on two spring, size and shape can be different. After removing the force from the spring, spring should restore itself back to the initial shape and size. Only accord with all the requirement above, we only then say that spring is obeying Hooke's Law.

Here's the example:

http://www.schoolphysics.co.uk/age11-14/Matter/text/Stretching_things/index.html

1) Different force is applied on the spring.

2) Spring deformed.

3)When force is removed, spring will restore itself to original size and shape.

On the experiment:

Material 1 and 2 obey the Hooke's Law as it return to the initial shape and size.

Material 3 did not obey Hooke's Law as it is permanent deformed. 

Difference between graphs

                        Graph 1                                                Graph 2                                        Graph 3

• Graph 1 is material 1 and it has gradient of 2.0583 and y-interception of 0.2, which give us equation of y = 2.0583x + 0.2.
• Graph 2 are material 1 and 2, material 2 have gradient of 1.5583 and y-intercept of 1.375, this gives us equation of y = 1.5583x + 1.375.
• Interception of x in graph 2 is 2.352.
• Graph 3 is material 3, it is a exponential graph where it's gradient will increase from infinite close to 0 to infinite close to 1, it means that it will never intercept the x - axis or the y - axis. The equation of this graph is y = 2.6257e to the power of 0.6853x.

Possible Error

• Eye may not read the reading accurately.
• Spring is not in the state of balanced force and reading is already taken. 
• Mass is not exactly the same as it stated, there might be a slight difference.