Mg=kx
kx^2/2+mv^2/2=mgh+k(x-h)^2/2
h-?
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x=mg/k
kx^2/2-k(x-h)^2/2+mv^2/2=mgh
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x=mg/k
kh*(2x-h)/2+mv^2/2=mgh
kh*(2mg/k-h)/2+mv^2/2=mgh
mgh-kh^2/2+mv^2/2=mgh
mv^2/2=kh^2/2
h=v*корень(m/k)=1*корень(1,6/250) м =0,08 м = 8 см