Math Question


Dawg

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A backhoe weighing 8 tons is on top of a flatbed 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, reinforced with 1 1/2 inch steel rebar spaced at 6 inch intervals in a criss-cross pattern layered at 1 foot vertical spacing.

Solve: 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: Solve for time and distance required for the entire rig to come to a complete stop after hitting the overpass at the speed calculated above?

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Backhoe1.jpg

backhoe3.jpg

backhoe2.jpg

I couldn't solve it either, but who cares.....the pics are GREAT!!!!!

Edited by Dawg
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I come up with 261 mph and .885071 seconds to stop. Distance obviously is the width of the bridge.......duh:rolleyes:

So from my calculations, the driver of the truck will get a speeding ticket:D, the engineers working for the manufacturer of the excavator will get some big raises $$$:eek:, and the guys who built the overpass will get their _sses jacked.:cool:

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Solve: 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...

Based on the distance it has sliced through the bridge thus far, according to my calculations, the Flatbed would have to be going exactly 2.37 times faster than it's previous speed to slice all the way through the bridge. :D:D:D:confused:

I would have hated to be the driver going past up top, at the time. :eek:

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