Typical Engineering Question or Bridge Bashing!

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A JCB weighing 22 tons is on top of a lowboy trailer and heading east on Interstate 70 near Hays, Kansas ..

The extended shovel arm is made of hardened refined steel and the approaching overpass is made of commercial-grade concrete, re-inforced with 1 1/2 inch steel rebar spaced at 6 inch intervals in a criss-cross pattern layered at 1 foot vertical spacing.

Question:

When the shovel arm hits the overpass, how fast do you have to be going to slice the bridge in half ?

(Assume no effect for headwind and no braking by the driver...)

Extra Credit:

What is the time and distance required for the entire rig to come to a complete stop after hitting the overpass at the speed calculated above.

Yes, you can neglect friction.

No, I couldn't solve it either......but who cares;

The pictures are great! 

Apparently the driver was on his cell phone..................

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