The four wheels of an automobile of mass equal to 1420 kg are suspended below the body by vertical springs of k = 6.40 104 N/m. If the forces on all wheels are the same, what will be the maximum instantaneous deformation of the springs if the automobile is lifted by a crane and dropped on the street from a height of 0.78 m?
The springs have to absorb all the kinetic energy of the falling car
Ke = m g h where h is the fall distance.
so
m g h = (1/2) * 4k * x^2