[填空题]
A bungee jumper with mass 65.0 kg +hsehdkw 3r(a: d.ep1jumps from a high bridge. j9kuymib mecswv1p)h. l8h( 2 n+-o /oAfter reaching his lowest point, he oscillates up and down, hitting )hw9mk-hp l.ojo+niyu2 sem8 /cvb(1 a low point eight more times in 38.0 s. He finally comes to rest 25.0 m below the level of the bridge. Calculate the spring stiffness constant and the unstretched length of the bungee cord.
spring stiffness constant$\approx$ N/m(Round to the nearest integer)
unstretched length of the bungee cord m