[填空题]
By how much does the gra+scw5k(n; 3p yn c qwi+yj46dvat+k.nvitation4 cdj kr2lw79 fs6p/jhzmo.k0 ss+/lxal potential energy of a 64-kg pole vaulter change if his center of mass rises about 4.7k 4hj.w s0okf /p 6+lcxm/ rdszs92lj0 m during the jump? J
