[填空题]
A 1200-kg car rollin ybc**ehfs)g .elzl, 7g on a horizontal r 6b)e +hhwwdh-;te 1asurface has speed v = 65 km/h when it strike h1 6 twd)wehe;a+hb-rs a horizontal coiled spring and is brought to rest in a distance of 2.2 m. What is the spring stiffness constant of the spring? N/m
