[问答题]
When an object falls freely under the intg8 t5 l;9n9,hgxs t4x5frmotpx6v6n81n a refluence of gravity there is a netpntr enn+o4n0lky): o0 dat95 force mg exerted on it by th5 n4ne:ydp09+no n lt)tk0 oare Earth. Yet by Newton’s third law the object exerts an equal and opposite force on the Earth. Why doesn’t the Earth move?
