( ( ( ( ( ( It ( an object ) ) ( is ( placed ( ( two earth-radii ) ( above ( ( the surface ) ( of ( the earth ) ) ) ) ) ) ) ) , ) then ) ( ( ( the force ) ( of ( ( gravitational attraction ) ( between ( ( ( the object ) and ) ( the earth ) ) ) ) ) ) ( will ( be ( one-fourth ( ( ( the magnitude ) as ) ( on ( ( earth 's ) surface ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NP (PRP It)) (NP (DT an) (NN object))) (VP (VBZ is) (VP (VBN placed) (NP (NP (CD two) (NNS earth-radii)) (PP (IN above) (NP (NP (DT the) (NN surface)) (PP (IN of) (NP (DT the) (NN earth))))))))) (, ,) (RB then) (S (NP (NP (DT the) (NN force)) (PP (IN of) (NP (NP (JJ gravitational) (NN attraction)) (PP (IN between) (NP (NP (DT the) (NN object)) (CC and) (NP (DT the) (NN earth))))))) (VP (MD will) (VP (VB be) (VP (VBN one-fourth) (PP (ADVP (NP (DT the) (NN magnitude)) (RB as)) (IN on) (NP (NP (NN earth) (POS 's)) (NN surface))))))) (. .)))
It an object is placed two earth-radii above the surface of the earth, then the force of gravitational attraction between the object and the earth will be one-fourth the magnitude as on earth's surface.
(ROOT (S (NP (NP (NNS Objects)) (PP (IN on) (NP (NN earth)))) (VP (VBP have) (NP (NP (CD two) (NNS forces)) (VP (VBG acting) (PP (IN on) (NP (PRP them))) (PP (IN at) (NP (DT all) (NNS times)))))) (. .)))