A 900 kg car rolling on a horizontal surface has speed v = 60 km/h when it strikes 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?

Question

A 900 kg car rolling on a horizontal surface has speed v = 60 km/h when it strikes 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?
  I solved this and i had 25826.44629, but i am being told i am wrong. please i need help with this.

bobpursley · Answer

1/2 m v^2=1/2 k x^2 k= mv^2/x^2 be certain to change km/hr to m/s