( ( ( Common types ) ( of ( potential energy ) ) ) ( ( are ( elastic ( , ( gravitational ( , ( chemical ( , ( ( electrical and ) nuclear ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (JJ Common) (NNS types)) (PP (IN of) (NP (JJ potential) (NN energy)))) (VP (VBP are) (ADJP (JJ elastic) (, ,) (JJ gravitational) (, ,) (JJ chemical) (, ,) (JJ electrical) (CC and) (JJ nuclear))) (. .)))
Common types of potential energy are elastic, gravitational, chemical, electrical and nuclear.
(ROOT (S (S (VP (VBG Changing) (NP (NP (DT the) (NN shape)) (PP (IN of) (NP (DT an) (JJ elastic) (NN material)))))) (VP (VBZ gives) (NP (PRP it)) (NP (JJ potential) (NN energy))) (. .)))