Starter

3 4 5 6 7 8 9 10 11 12 130

1

2

3

4

5

6

7

8

9

f(x) = 0.502271580010096 x + 1.98182735991923

stretch (m)

Force (N)

1. What is the spring constant for this spring?

2. What is the meaning of the y-intercept?

Starter Hooke’s Law

If a 1kg mass stretches a spring 2.5cm, what mass would stretch it 10cm?

Hooke’s Law for SpringsThe force required to stretch a spring is directly proportional to how much it is stretched, or :

F = kxF = stretching force in Newtonsx= stretch in metersk = the spring constant in N/m

ExampleWhen a .5kg mass is hung on a spring, it stretches .25m.

1. What is the spring constant?

k = F/x = mg/x = .5(9.8)/.25 = 19.6 N/m

2. How much would a 2kg mass stretch the spring?

x = F/k = 2(9.8)/19.6 = 1.00m

Hooke’s Law F =kx

If you plot the stretching force on the y axis, and the amount of stretch on the x axis, what will the plot look like?

3 4 5 6 7 8 9 10 11 12 130

1

2

3

4

5

6

7

8

9

stretch (m)

Force (N)

What does the slope represent?

Slope = k

Practice - Hooke’s Law

m (kg) x(m) F (N)

0.00 0.00  0.00

.050 .045 .441

0.100 0.090 .980

P

Elastic Forces - Hooke’s Law

F = kx k = 10.9 N/m

Application - Springs

Design an experiment to determine the spring constant for: 2 of the color coded springs 1 of the silver springs. A rubber band

Make a F vs. x graph for each with 5 data points.Show a best fit line and determine the equation and k.

A

Sample Data table

Spring Color ______________

Plot on x-axis Plot on y-axis

Trial m (kg) x(m) F (N)

1      

2      

3      

4

5

Question

1. Did the rubber band obey Hooke’s Law? Explain.

Lab Report Checklist

1.Starter2.Data Tables (4)3.F vs. x Graphs (4) with slopes4.Experimental k values (4)5.Question6.Connection7.Summary

Connection

What real life applications of Hooke’s Law have you observed?

C

EXIT

Summarize your experiment including the objective, the procedure, the results, and reasons for error.

E