Computer Applications Assignment 1
Wan Ahmad Nuruddin Nafis Bin Wan Abdul Hakim
29772885
Introduction
When a force is applied to an elastic material, it stretches or compresses.Robert Hooke realized that a stress vs strain graph would have a linear region.The force is directly proportional to the extension of a material,such as a spring, as long as the material does not exceed its elastic limit.This is known as Hooke's Law.It is written as an equation:
F = kx
where F is the force applied,(N),
where k is the spring constant,(N/m),and
x is the spring extension,(m)
The graph of Force(N) versus the extension(m) is a linear graph
Spring constant k is the gradient of the graph.
Plastic Deformation happens when a force is continuously put on an object until beyond its elastic limit where it will not return to its original state.For example,a string will not return to its original length when it is stretched beyond its elastic region.
Aim of the Experiment
Plastic Deformation happens when a force is continuously put on an object until beyond its elastic limit where it will not return to its original state.For example,a string will not return to its original length when it is stretched beyond its elastic region.
Aim of the Experiment
The aim of the experiment is to investigate the behavior of materials in relation to Hooke's Law.
The first two materials, which are from two different type of material, are still in their linear regions.
The last material is in its plastic region.
The results will be analysed, put into graphs and a conclusion will be made.
Methods
Diagram 1
1. The apparatus is set up as in Diagram 1.
2. Material 1 on one end is clamped and hung vertically in line with the meter ruler.
3. A force is applied to the other end of the material.
4. The extension is measured and recorded using the meter ruler.
5. Step 3 is repeated 9 times with a bigger force.
6. Step 2 to 5 is repeated with materials 2 and 3.
The results of material y2 and material z are calculated on Microsoft Excel 2016 using the formula given :
y2=(a+0.5)x+c ,and
z=x^3+b
where a=1.5583
b=1.375
c=0.2
y1 is material 1,
y2 is material 2,and
z is material 3
The results of the experiment is :
Diagram 2
Graphs are plotted using the results :
Diagram 3
The graph in Diagram 3 shows the deformation(y1/y2) of material 1 and 2 against the force applied (x).It iss a linear graph for both materials 1 and 2.This means that they are in their elastic region and that Hooke's Law still holds good for these materials.
Diagram 4
The graph in Diagram 4 shows the deformation of material 3 (z) against the force applied (x).The shape of the graph confirms that the material is in its plastic region and that Hooke's Law is no longer valid.
Calculations
Based on Diagram 3, the two lines is of y1 and y2 meets at an estimated points of (2.40,5.00).Using simultaneous, the real meeting points can be found.
y1=1.5583x+1.375 ---1
y2=(1.5583+0.5)x+0.2 ---2
put 1 into 2
2.0583x+0.2=1.5583x+1.375
0.5x=1.175
x=2.35
y=(1.5583+0.5)x+0.2
y=(2.0583)2.35+0.2
y=5.037
Real meeting points of y1 and y2 is = (2.35,5.037)
Discussion
Based on the graphs, there might be a couple of possible errors that influenced the result of this experiment.One of the errors are:
Parallax Error
Parallax error happens when the measurements are not read at the correct angle, which resulted in the inaccuracy of measurements.In this case, when the measurements of deformation on the meter ruler is taken by one.
Significant Figures
The values of y2 and z were rounded off to two decimal places.This may have affected the final result.
The labels on the meter ruler could be a little off, and it may not have been accurate due to some fault.
Conclusion
The result obtained for materials 1,2 and 3 are ideal as it correlates with Hooke's Law. The deformation of material 1 and 2 as shown in the results are in the elastic limit.Because of this, the graphs of y1(deformation for material 1) and y2(deformation for material 2) against x(force) is a linear graph.It shows that the force applied is directly proportional to the deformation of both materials.Based on Diagram 3 , the gradient of y2 is more than y1, which means that material 2 is more elastic.
For both material 1 and 2, if the force is taken away, both materials will return to its original state.
For material 3, it is already in the plastic region and cannot return to its original state as shown in Diagram 4.The curve of the graph shows that the material is deformed.
References
Anon, KS3 Physics - Forces - Revision 9. BBC Bitesize. Available at: https://www.bbc.co.uk/education/guides/zttfyrd/revision/9.
Anon, Physics 1 Dynamics Experiment How Does A Spring Scale Work? Hooke's Law. Dynamics - Hooke's Law Experiment. Available at: http://www.batesville.k12.in.us/physics/phynet/mechanics/newton3/labs/SpringScale.html.
The Editors of Encyclopædia Britannica, 2016. Hooke's law. Encyclopædia Britannica. Available at: https://www.britannica.com/science/Hookes-law.
Anon, What is Hooke's Law? (article). Khan Academy. Available at: https://www.khanacademy.org/science/physics/work-and-energy/hookes-law/a/what-is-hookes-law.
