Bobble-head. A football bobble-head figure sits on your car dashboard. The 85-g head of...

Bobble-head. A football bobble-head figure sits on your car dashboard. The 85-g head of the figure is attached to a spring with spring constant k = 21 N/m (Fig. P11.69). You are driving along a straight road when you notice a series of hoses lying across the road, perpendicular to your motion, that cannot be avoided, and you drive over them. If the hoses are spaced exactly 4.0 m apart, what speed should you avoid so your bobble-head figure does not sustain damage from its head vibrating too hard at maximum amplitude?