what is a typical K for a pogo stick spring? and waht's the average attainable jump height?

Answer 1

I have no clue. The k will will most definitely probably vary among manufactures. However we can estimate.

F=mg=kx
Let
m=60 kg (132lb mass)
x= 10cm
g=9.81m/s^2
we have
k=mg/x=60 x 9.81/0.1=5886 M/m

the max height h can be computed by adding energy provided by the jumper plus energy stored in the spring.

Potential energy P at the very top of height h
P=(m1+m2)gh=Ke+Ps

Ke - kinetic energy of a jumper at the ground level who jumps with initial speed V
Ps - Potential energy in the compressed pogo spring
m1- mass of the jumper
m2- mass of the pogo stick
Ke=.5mV^2
Ps=.5kx^2

finally
h=(.5 mv^2 + .5 kx^2)/[(m1+m2)g]