Spring constant/kinetic energy

[kavipach]

1. The problem statement, all variables and given/known data

If you stand on a bathroom scale, the spring inside the scale compresses 0.55mm, and it tells you your weight is 760 N.
Now if you jump on the scale from a height of 1.3m, what does the scale read at its peak?

2. Relevant equations
F=kx
K.E=1/2mv^2


3. The attempt at a solution
I tried alot of things but i cant get the answer

[v_bachtiar]

I tried alot of things but i cant get the answer
Try more... :smile:

Well one more equation you need to know

Elastic potential energy = Eep = 0.5 kx2

I'm sure you know how to get the spring constant, k
And then find the total energy of the system E = mgh

then substitute the E value you got to the equation
Eep = 0.5 kx2 to find x

(at the "peak", all of the kinetic energy + gravitational potential energy is converted to elastic potential energy)

then since you know the x (compression) at the peak value
substitute to F = kx to get the F value for the scale value it reads

That's what i would do.
I can very well be wrong

[songoku]

you've posted this before
http://www.physicsforums.com/showthread.php?t=325531

[JazzFusion]

Very well explained, V_B!

[songoku]

Thx LOL ^^