( ( Magnetic spring ) ( ( suspension ( I ( use ( ( ( the repulsion ) ( between ( ( two magnets ) ( as ( a ( spring force ) ) ) ) ) ) ( to ( ( balance ( ( ( ( the force ) ( of gravity ) ) ( rather than ) ) ( the metal ) ) ) spring ) ) ) ) ) ) ( ( ( more commonly ) ( used ( in ( vertical seismographs ) ) ) ) . ) ) )
(ROOT (S (NP (JJ Magnetic) (NN spring)) (NP (NP (NN suspension)) (SBAR (S (NP (PRP I)) (VP (VBP use) (S (NP (NP (DT the) (NN repulsion)) (PP (IN between) (NP (NP (CD two) (NNS magnets)) (PP (IN as) (NP (DT a) (NN spring) (NN force)))))) (VP (TO to) (VP (VB balance) (NP (NP (NP (DT the) (NN force)) (PP (IN of) (NP (NN gravity)))) (CONJP (RB rather) (IN than)) (NP (DT the) (NN metal))) (NP (NN spring))))))))) (VP (ADVP (RBR more) (RB commonly)) (VBN used) (PP (IN in) (NP (JJ vertical) (NNS seismographs)))) (. .)))
Magnetic spring suspension I use the repulsion between two magnets as a spring force to balance the force of gravity rather than the metal spring more commonly used in vertical seismographs.
(ROOT (S (NP (NNP Gravity) (CC and) (NNP magnetism)) (VP (VBP are) (NP (DT both) (JJ common) (NNS forces))) (. .)))
Gravity and magnetism are both common forces.