[填空题]
A pilot performs an evasive maneuver by diving vertically at 37ewsf+pmegv4; e 3y3 9njyv 5s10:4 v w8zyki dz8dk2)qa $\mathrm{~m} / \mathrm{s}$ . If he can withstand an acceleration of 9.0 g 's without blacking out, at what altitude must he begin to pull out of the dive to avoid crashing into the sea?
