1. Elastic Forces
Hooke’s Law

2. Hooke’s Law
The restoring force exerted by an object (FS) is proportional to the amount it is stretched or compressed (x) and its ‘spring constant’ (k)
FS = kx

3. Hooke’s Law applies to THIS
region ONLY!

4. Example #1
A spring with a spring constant of 10 newtons per meter is stretched 0.5 meter. What force must be applied to the spring?
FS = kx
FS = (10 N/m)(0.5 m)
FS = 5.0 N

5. Example #2
What is the spring constant of an elastic object if it stretches 2.0 centimeters when pulled with a force of 30 newtons?
FS = kx k = FS / x
k = (30 N)/(0.02 m)
k = 1500 N/m

6. End of PRACTICE