Transcript The Creation of the Earth

Spring Notes
Hooke’s Law Definition:
The extension (stretch) of a spring
is directly proportional to the force
applied to it
Equation: Fs = kx
Fs = Force in the spring (N)
K = Spring constant (N/m)
X = Stretch/compress distance (m)
K Values
Large K values = Stiff spring  takes a lot of
force to stretch
Small K values = Loose spring  very little
force needed to stretch
Elastic
Definition:
Potential
The energy stored in an elastic
Energy (EPE)
object when it is stretched
Equation: EPE= ½ kx2
K = Spring constant (N/m)
X = Stretch/compress distance (m)
*Which kind of spring would store more
energy? Stiff or loose? Explain why.
Stiff spring because takes a lot more
force to stretch it.
Practice 1. Rich (70kg) is jumping off his garage again (3m high), but this time he is
Problems 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.
Beginning
GPE
KE
TE
EPE
Total
End
2058
0
0
0
2058
0
0
0
2058
2058
b.) Calculate PE, KE, TE, EPE and Total Energy at the
beginning and end of his motion. Add to the chart above.
GPE=70(9.8)(3)
GPE= 2058 J
Total=2058 J
c.) Calculate Rich’s velocity at the end of his motion.
EPE=1/2 kx2
2058=1/2(6000)x2
2058=3000x2
.686=x2
x=.83 m