How many times have you wondered how strong those cement barriers are that you see in front of military base entrances???? 

Read below and then view the clip...  From time to time someone asks what the concrete barriers are in front of controlled and secure buildings.  When they are told that the barriers will stop traffic, even trucks, from approaching the secure building, they usually get a look of disbelief.  In the following test, the following parameters were used.  Read them and then watch the film/Clip.

Truck = 65,000 lbs.
Speed = 50 mph
Kinetic Energy = 5.5 MILLION ft. lbs.
Stopped in 24 inches !!!

View the video Cement Barriers (1.8 mb)