( ( ( ( Field lines ) and ) ( equipotential lines ) ) ( ( are ( perpendicular ( to ( each other ) ) ) ) . ) )
(ROOT (S (NP (NP (NNP Field) (NNS lines)) (CC and) (NP (JJ equipotential) (NNS lines))) (VP (VBP are) (ADJP (JJ perpendicular) (PP (TO to) (NP (DT each) (JJ other))))) (. .)))
Field lines and equipotential lines are perpendicular to each other.
(ROOT (S (SBAR (IN Since) (S (NP (DT the) (JJ electric) (NN field) (NNS lines)) (VP (VBP point) (ADVP (RB radially)) (ADVP (RB away) (PP (IN from) (NP (DT the) (NN charge))))))) (, ,) (NP (PRP they)) (VP (VBP are) (ADJP (JJ perpendicular) (S (VP (TO to) (VP (VB equipotential) (NP (NNS lines))))))) (. .)))