Hooke's Law Lab Report

NAME: Nur Syahirah Bt Mohamad Hanafi TITLE: Hooke’s Law Experiment DATE: 22nd August 2013 AIM: To determine whether a given spring obeys Hooke’s law. PARTNER: Tengku Maimunah Bt Tengku Iskandar Nur Adilla Bt Abdul Kadir Data Collection and Processing Initial length, ℓₒ= 3.50 ± 0.05 cm Mass/g

Mass/kg

50 100 150 200 250 300 350 400 450 500

0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50

Load= mg,F,(N) 0.05g 0.10g 0.15g 0.20g 0.25g 0.30g 0.35g 0.40g 0.45g 0.50g

Load= mg,F,(N) 0.05g 0.10g 0.15g 0.20g 0.25g 0.30g 0.35g 0.40g 0.45g 0.50g

0.50 1.50 2.50 3.50 4.50 5.50 6.50 7.50 8.50 9.50

4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00 13.00

4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00 13.00

Average extension ,(cm)

Extension,x= (cm), ( 0.50 1.50 2.50 3.50 4.50 5.50 6.50 7.50 8.50 9.50

Extended length, (cm), ( 0.05cm)

0.50 1.50 2.50 3.50 4.50 5.50 6.50 7.50 8.50 9.50

0.50 1.50 2.50 3.50 4.50 5.50 6.50 7.50 8.50 9.50

4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00 13.00 Extension’s uncertainty /cm

Sample calculation Reading of the extension x= = 4.00 – 3.50 = 0.50 cm Reading of the average extension

= = 0.50 cm Reading of average uncertainty of the extension

= = 0.10 Gradient of the graph k= = = 0.05

Conclusion and Evaluation Conclusion:A graph of load against the extension of spring resulted in the expected straight line and it is a linearly increased graph. A formula is derived:- F=kx WhereF=force k= spring constant x= extension of spring The spring constant, k, is the stiffness of the spring. It is determined by the value of the gradient of the graph. Using the formula of:k= As the load is added from time to time, the spring also extends proportionally. The extension restored to its original length when the load is removed. If a force stretches a spring beyond its elastic limit, the spring cannot return to its original even though the force no longer acts on it. The hooke’s law is not obeyed anymore. According to the theory of hooke’s law, F . The graph should be a directly proportional graph. There are few reasons for getting a linearly increased graph. Such as, the spring has exceeded its elastic limit, resulting in a non uniform extended length. By using a new spring, it can reduce the systematic error. The graph does not have an error bar on the x-axis because the uncertainty is too small, such that the error bar cannot be shown on the graph. While on the y-axis, there is no error bar because there is no uncertainty for the load as the load is constant. Other than that, the spring sways during the experiment due to the movement of air from the fans that were left on. So, by turning off the fans, it might reduce the error.