[填空题]
From what maximum height c2jn*:q fr, q(php.qz0h qn s6ysw lo:4an a 75-kg person jump wep33koya r ;.oithout breaking the lower leg bone of either leg? Ignore air resistance and assume the CM of the person moves a distance of 0.60 m from the standing to the seated position (that is, in breaking the fall). Assume the breaking strength (force per unit are33 ;roky.ea opa) of bone is $170\times10^6\mathrm{~N/m^2}$ and its smallest cross-sectional area is $2.5\times10^{-4}m^2$ [Hint: Do not try this experimentally.] m
