JT4x4

The Mud Pit => General => Topic started by: WillC on February 07, 2009, 08:56:10 PM

Title: Math Question:
Post by: WillC on February 07, 2009, 08:56:10 PM: An excavator 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 chris -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 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.

(http://i652.photobucket.com/albums/uu242/will-aj/untitled1.jpg)

(http://i652.photobucket.com/albums/uu242/will-aj/untitled2.jpg)

(http://i652.photobucket.com/albums/uu242/will-aj/untitled3.jpg)

I couldn't solve it either......but who cares;
the pictures are great!
Title: Re: Math Question:
Post by: PaulW on February 08, 2009, 01:23:20 AM: y would they be traveling with the arm up anyway??
Title: Re: Math Question:
Post by: BayouGold on February 08, 2009, 01:24:13 AM: bet the driver wishes he could click his heels three times to get the heck outa kansas!
Title: Re: Math Question:
Post by: Axle on February 08, 2009, 02:48:23 AM: :D Now that's funny, Geoff!
Title: Re: Math Question:
Post by: calvynandhobbs on February 08, 2009, 04:08:34 AM: I bet there were a lot of angry commuters that day, but it is funny since I didn't have to sit in the traffic jam.
Title: Re: Math Question:
Post by: rocket on February 08, 2009, 06:43:43 AM: Quote from: PaulW on February 08, 2009, 01:23:20 AM
y would they be traveling with the arm up anyway??

bet you $20 that the arm was down, however, in the lowered position, it was still too high for the overpass. the first part to fail was the hydraulic system which allowed the arm to be forced back to vertical and slice into the bridge.
Title: Re: Math Question:
Post by: HOT-ROD on February 11, 2009, 03:42:15 AM: :o

BRILLIANT!!
Title: Re: Math Question:
Post by: rocket on February 11, 2009, 03:57:41 AM: Its not like i'm an engineer.
Title: Re: Math Question:
Post by: Axle on February 11, 2009, 04:14:20 AM: Quote from: rocket on February 11, 2009, 03:57:41 AM
Its not like i'm an engineer.

I don't think he was talking about you, but you're purty smart. ;)
Title: Re: Math Question:
Post by: HOT-ROD on February 11, 2009, 04:15:49 AM: lol
Title: Re: Math Question:
Post by: PaulW on February 11, 2009, 07:15:30 AM: Quote from: rocket on February 08, 2009, 06:43:43 AM
Quote from: PaulW on February 08, 2009, 01:23:20 AM
y would they be traveling with the arm up anyway??

bet you $20 that the arm was down, however, in the lowered position, it was still too high for the overpass. the first part to fail was the hydraulic system which allowed the arm to be forced back to vertical and slice into the bridge.

oh