1. Spring Notes

2. Hooke’s Law
Definition:
Equation:
K Values
Large K values =
Small K values =
The extension (stretch) of a spring is directly proportional to the force applied to it
Fs = kx
Fs = Force in the spring (N)
K = Spring constant (N/m)
X = Stretch/compress distance (m)
Stiff spring  takes a lot of force to stretch
Loose spring  very little force needed to stretch

4. Elastic Potential Energy (EPE)
Definition:
Equation:
*Which kind of spring would store more energy? Stiff or loose? Explain why.
The energy stored in an elastic object when it is stretched
EPE= ½ kx2
K = Spring constant (N/m)
X = Stretch/compress distance (m)
Stiff spring because takes a lot more force to stretch it.

5. 2058 2058 2058 2058 GPE=70(9.8)(3) GPE= 2058 J Total=2058 J
Practice Problems
1. Rich (70kg) is jumping off his garage again (3m high), but this time he is landing on a trampoline. The spring constant for the trampoline is 6000N/m.
a.) Draw an energy chart to show the GPE, KE, TE, EPE and total energy at the beginning and end of his motion.
b.) Calculate PE, KE, TE, EPE and Total Energy at the beginning and end of his motion. Add to the chart above.
c.) Calculate Rich’s velocity at the end of his motion.
Beginning
End
GPE KE TE
EPE
Total
2058
2058
2058
2058
GPE=70(9.8)(3)
GPE= 2058 J
Total=2058 J
2058=1/2(6000)x2
2058=3000x2
.686=x2
x=.83 m
EPE=1/2 kx2