Changing position moves energy between spring and motion while the total stays exact. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

At the endpoint the spring holds the full total

Position 4 m gives spring energy 16 J and kinetic energy 0 J. Their sum stays 16 J.

U+K=16 J+0 J=16 JU+K=16\ \mathrm{J}+0\ \mathrm{J}=16\ \mathrm{J}
Energy split scanSpring, kinetic, and total energy are checked.k=2 N/mA=4 mx=4 mE=16 JU=16 JK=0 J

Half displacement leaves most energy kinetic

Position 2 m gives spring energy 4 J and kinetic energy 12 J. Their sum stays 16 J.

U+K=4 J+12 J=16 JU+K=4\ \mathrm{J}+12\ \mathrm{J}=16\ \mathrm{J}
Energy split scanSpring, kinetic, and total energy are checked.k=2 N/mA=4 mx=2 mE=16 JU=4 JK=12 J

At the center all stored energy is kinetic

Position 0 m gives spring energy 0 J and kinetic energy 16 J. Their sum stays 16 J.

U+K=0 J+16 J=16 JU+K=0\ \mathrm{J}+16\ \mathrm{J}=16\ \mathrm{J}
Energy split scanSpring, kinetic, and total energy are checked.k=2 N/mA=4 mx=0 mE=16 JU=0 JK=16 J