Name_____________________
Date:_______________
Hooke’s Law Lab
Objective: To determine the spring constant for a hanging spring.
Background: An empirical relationship is one that is obtained by experiment or observation rather than
from theory. Such a relationship was established by Robert Hooke, (1635-1703), regarding the amount
of force on a spring and the amount it stretches. The formula that Hooke came up with is known as
Hooke’s law.
Fs = kx
Where F is the force applied to the spring, x is the spring’s change in length from its equilibrium
position and k is a quantity called the “spring constant.” If a graph of force vs. distance stretched is
made, the slope of that line will determine the spring constant.
Materials:
o Hooke’s law apparatus
o Masses
Procedure:
1.
2.
3.
4.
5.
Hang the spring from the support.
Adjust the scale so that the bottom of the hanger (or the pointer) reads 0.0 cm.
Place a mass on the spring. Record the value of this mass, in kg, in your data table.
Record the spring’s new length, and determine the change in its length in cm and m.
Repeats steps 3 & 4 for different masses.
Trial
1
2
3
4
5
6
7
8
9
10
Mass (kg)
Force (N)
Elongation (cm)
Elongation (m)
Graphical Analysis:
1.
2.
3.
4.
5.
6.
7.
8.
Hold the graph paper so that the long side is horizontal.
Label the long side (the x axis) “Elongation, x”
Label the short side (the y axis) “Force, F”
Using your data in the “Elongation” column, find the largest appropriate scale.
Using your data in the “Force” column, find the largest appropriate scale.
Plot your data. Remember to place a circle around each data point.
Draw the line or curve of best fit. DO NOT play connect the dots!!
Calculate the slope of your graph. Show your work on the graph itself.
Questions: (ANSWER IN COMPLETE SENTENCES!)
1.
Based on the shape of your Force vs. Elongation graph, is Hooke’s Law a direct, inverse, or
square relationship? Justify your response.
2.
What is the slope of an F vs. x graph called?
3.
What was the potential energy stored in the spring when you added the maximum amount of
weight?
Conclusion: (Be complete!!)