How many times have you wondered how strong those cement barriers are
that you see in front of military base entrances?Huh
Read below and then view the clip...
From time to time someone asks me what the concrete barriers are in
front of controlled and secure buildings. When I tell them that the barriers
will stop traffic, even trucks, from approaching the secure building I
usually get a look of disbelief.
I've been looking for some footage like this to prove my point. In
this test, the following parameters were used. Read them and then watch the
film.
Truck = 65,000 lbs.
Speed = 50 mph
Kinetic Energy = 5.5 MILLION ft. lbs. Remember: KE=MV2
Stopped in 24 INCHES!!!

http://www.phillippi.us/yabb/yabbse/Dow ... arrier.WMV