To Determine The Spring Constant(K)
Aim: To determine the spring constant(k).
Introduction: Force applied on a spring to elongate it. The weights of the masses are the
forces on the spring.
Applied force=WEIGHT
Weight is the gravitational force on the objects.
Weight is equal to mass times gravity acceleration.
W=m.g
Weight(W) has a unit of N
Mass(m) has a unit of kg.
Gravity acceleration(g) has a unit of kgms-2.
The extension of the spring is measured by initial and final length of the spring.
Extension=final length – initial length
Extension(e) has a unit of cm.
To find the spring constant k, we use the equation below.
F=k.e
The SI unit of the spring constant is Nm-1
First, we got a spring and a mass hanger at one end of it. And we used a ruler to measure the
initial length of the spring. Then we put 100 g of mass on the mass hanger and measure the
final length of the spring. We repeated the same procedure for 200 g to 900 g. We did nine
trials to get our datas. The dependant variable is extension and the independent variable is
mass for this experiment. Significant controlled variable is the spring.
Conclusion and evaluation: For the spring constant k, we found k=0.1163±0.0009Ncm-1. The
real result is k=11.63±0.09Nm-1 in SI unit.
The spring constant k, is a measure of the stiffness of the spring. It has a indirect proportion
with extension, so measure in the mass and extension of the spring several times and
recording them than dividing the weight by the extension should give us the spring constant.
The range of uncertainty is calculated by using the uncertainties of weight and extension. The
percentage error can not be calculated since no literature value for the spring constant has
been given to us. We can not also compare our results range to the accepted value since no
such value exists. The sources of error in our experiment were that the uncertainty of masses
and the uncertainty of the ruler and those influenced our result. The uncertainty of our
masses was very small compared to that of the ruler's. It did not affect our result at all since
during the graphing the error bars were to small for the weights. The ruler on the other hand
gave us an uncertainty that was enough to draw error bars. The main source of error arising
from the experimental method during the measuring by the ruler, our precision was not
enough because of the spring's little ossilation. We were not efficient with our time since it
took lots of time to measure the lengths of the spring while it was ossilating. We think that if
we had not to wait for the end of ossilations so much, we could have easily done more than
five trials.