- #1
the_awesome
- 56
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Hey guys. I'm trying to figure out the spring constant of a bungee cord.
Weight = 80kg
Gravity = 9.8m/s/s
Length of cord = 10m
Length of jump = 50m
I've been shown two different methods. And I don't know which one is correct because they give two different answers :/
1.
k = F/x = mg/x
Also knows as : k=Fx/x-x0
So i substitute: k= (80kg x 9.8) / (50-10)
k= 19.6 N/M
2.
PE=mgh
KE=0.5mv^2 = 0.5kx^2
F= -kx
mgh=0.5kx^2
80 x 9.8 x 50 = 0.5k x 40^2
therefore k= 49
So which method is correct? One gets 19.6, the other gets 49.
Weight = 80kg
Gravity = 9.8m/s/s
Length of cord = 10m
Length of jump = 50m
I've been shown two different methods. And I don't know which one is correct because they give two different answers :/
1.
k = F/x = mg/x
Also knows as : k=Fx/x-x0
So i substitute: k= (80kg x 9.8) / (50-10)
k= 19.6 N/M
2.
PE=mgh
KE=0.5mv^2 = 0.5kx^2
F= -kx
mgh=0.5kx^2
80 x 9.8 x 50 = 0.5k x 40^2
therefore k= 49
So which method is correct? One gets 19.6, the other gets 49.