Hookes Law Physics Experiment 8

Hooke’s Law

Lab Report
Please complete the following tables and questions and submit them on Blackboard.

Observations
Data Table 1.

Force (N)
Top position of spring, cm
Bottom position of spring, cm
Elongation, cm
Bottom reading – top reading
Data Point 1
.8
4
5
1
6Data Point 2
1.3
4
6
2
Data Point 3
1.5
4
7
3
Data Point 4
2
4
8
4
Data Point 5
2.2
4
9
5
Data Point 6
2.5
4
10
6
Data Point 7
2.7
4
11
7
Data Point 8
3
4
12
8
Data Point 9
3.3
4
13
9
Data Point 10
3.6
4
14
10

Data Table 2.

Force (N)
Accumulated (cm) Elongation (stretch)
Accumulated (m) Elongation (stretch)
Elastic PE
(Joules)

Data Point 1
.8
1
.01
2
Data Point 2
1.3
2
.02
8
Data Point 3
1.5
3
.03
18
Data Point 4
2
4
.04
32
Data Point 5
2.2
5
.05
50
Data Point 6
2.5
6
.06
72
Data Point 7
2.7
7
.07
98
Data Point 8
3
8
.08
128
Data Point 9
3.3
9
.09
162
Data Point 10
3.6
10
.1
200

Calculations and Analysis
A. For each data row in each of your tables calculate: Elastic PE =

B. For each spring and the rubber band, plot the accumulated elongation (X-axis) versus the applied force (Y-axis) on a computer spreadsheet.

C. Find the spring constant for the springs in Newton/meters from the slope of each graph. (Refer to the Excel tutorial in the Introduction section). Spring constant, , where F is in Newton and x is in meters. Therefore, the units are N/m.

D. Find the “spring” constant for the rubber band from the slope of the curve using the linear portion of the graph.

Sample Graph. Rubber Band.

Questions
A. How does the relative stiffness of a spring relate to its spring constant? It appears that the larger the spring constant, the stiffer the spring is and more difficult it is to stretch out.

B. How does PE change relative to the stretch of the spring? As the spring is increasingly elongated, the PE is increased as well.

C. Indicate on your graph for the rubber band where the linear behavior stops. What does this mean? Between .25 and .3 (cumulative elongation, m) seems to be