1 1 (2) Ems=2m加=2mw2N=2.0x105J 2 (3)E=Ekmx=2.0×103J (4)Ek=E,时,E。=1.0×103J 2E=0.5×10'm2 mo x=±0.707cm( 2 ) 2 . 0 10 J − 3 = 2 2 2 k,max max 21 21 E = m v = m A ( 3 ) E = E k ,max 2 . 0 10 J − 3 = ( 4 ) E k = E p 时, 1 . 0 10 J 3 p − E = 由 2 2 2 p 21 21 E = k x = m x 2 2 2 p m E x = 4 2 0 . 5 10 m − = x = 0 .707cm